1 /*
   2  * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "asm/assembler.inline.hpp"
  27 #include "code/compiledIC.hpp"
  28 #include "code/debugInfo.hpp"
  29 #include "code/debugInfoRec.hpp"
  30 #include "compiler/compileBroker.hpp"
  31 #include "compiler/oopMap.hpp"
  32 #include "memory/allocation.inline.hpp"
  33 #include "opto/callnode.hpp"
  34 #include "opto/cfgnode.hpp"
  35 #include "opto/locknode.hpp"
  36 #include "opto/machnode.hpp"
  37 #include "opto/output.hpp"
  38 #include "opto/regalloc.hpp"
  39 #include "opto/runtime.hpp"
  40 #include "opto/subnode.hpp"
  41 #include "opto/type.hpp"
  42 #include "runtime/handles.inline.hpp"
  43 #include "utilities/xmlstream.hpp"
  44 
  45 #ifndef PRODUCT
  46 #define DEBUG_ARG(x) , x
  47 #else
  48 #define DEBUG_ARG(x)
  49 #endif
  50 
  51 // Convert Nodes to instruction bits and pass off to the VM
  52 void Compile::Output() {
  53   // RootNode goes
  54   assert( _cfg->get_root_block()->number_of_nodes() == 0, "" );
  55 
  56   // The number of new nodes (mostly MachNop) is proportional to
  57   // the number of java calls and inner loops which are aligned.
  58   if ( C->check_node_count((NodeLimitFudgeFactor + C->java_calls()*3 +
  59                             C->inner_loops()*(OptoLoopAlignment-1)),
  60                            "out of nodes before code generation" ) ) {
  61     return;
  62   }
  63   // Make sure I can find the Start Node
  64   Block *entry = _cfg->get_block(1);
  65   Block *broot = _cfg->get_root_block();
  66 
  67   const StartNode *start = entry->head()->as_Start();
  68 
  69   // Replace StartNode with prolog
  70   MachPrologNode *prolog = new (this) MachPrologNode();
  71   entry->map_node(prolog, 0);
  72   _cfg->map_node_to_block(prolog, entry);
  73   _cfg->unmap_node_from_block(start); // start is no longer in any block
  74 
  75   // Virtual methods need an unverified entry point
  76 
  77   if( is_osr_compilation() ) {
  78     if( PoisonOSREntry ) {
  79       // TODO: Should use a ShouldNotReachHereNode...
  80       _cfg->insert( broot, 0, new (this) MachBreakpointNode() );
  81     }
  82   } else {
  83     if( _method && !_method->flags().is_static() ) {
  84       // Insert unvalidated entry point
  85       _cfg->insert( broot, 0, new (this) MachUEPNode() );
  86     }
  87 
  88   }
  89 
  90 
  91   // Break before main entry point
  92   if( (_method && _method->break_at_execute())
  93 #ifndef PRODUCT
  94     ||(OptoBreakpoint && is_method_compilation())
  95     ||(OptoBreakpointOSR && is_osr_compilation())
  96     ||(OptoBreakpointC2R && !_method)
  97 #endif
  98     ) {
  99     // checking for _method means that OptoBreakpoint does not apply to
 100     // runtime stubs or frame converters
 101     _cfg->insert( entry, 1, new (this) MachBreakpointNode() );
 102   }
 103 
 104   // Insert epilogs before every return
 105   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
 106     Block* block = _cfg->get_block(i);
 107     if (!block->is_connector() && block->non_connector_successor(0) == _cfg->get_root_block()) { // Found a program exit point?
 108       Node* m = block->end();
 109       if (m->is_Mach() && m->as_Mach()->ideal_Opcode() != Op_Halt) {
 110         MachEpilogNode* epilog = new (this) MachEpilogNode(m->as_Mach()->ideal_Opcode() == Op_Return);
 111         block->add_inst(epilog);
 112         _cfg->map_node_to_block(epilog, block);
 113       }
 114     }
 115   }
 116 
 117 # ifdef ENABLE_ZAP_DEAD_LOCALS
 118   if (ZapDeadCompiledLocals) {
 119     Insert_zap_nodes();
 120   }
 121 # endif
 122 
 123   uint* blk_starts = NEW_RESOURCE_ARRAY(uint, _cfg->number_of_blocks() + 1);
 124   blk_starts[0] = 0;
 125 
 126   // Initialize code buffer and process short branches.
 127   CodeBuffer* cb = init_buffer(blk_starts);
 128 
 129   if (cb == NULL || failing()) {
 130     return;
 131   }
 132 
 133   ScheduleAndBundle();
 134 
 135 #ifndef PRODUCT
 136   if (trace_opto_output()) {
 137     tty->print("\n---- After ScheduleAndBundle ----\n");
 138     for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
 139       tty->print("\nBB#%03d:\n", i);
 140       Block* block = _cfg->get_block(i);
 141       for (uint j = 0; j < block->number_of_nodes(); j++) {
 142         Node* n = block->get_node(j);
 143         OptoReg::Name reg = _regalloc->get_reg_first(n);
 144         tty->print(" %-6s ", reg >= 0 && reg < REG_COUNT ? Matcher::regName[reg] : "");
 145         n->dump();
 146       }
 147     }
 148   }
 149 #endif
 150 
 151   if (failing()) {
 152     return;
 153   }
 154 
 155   BuildOopMaps();
 156 
 157   if (failing())  {
 158     return;
 159   }
 160 
 161   fill_buffer(cb, blk_starts);
 162 }
 163 
 164 bool Compile::need_stack_bang(int frame_size_in_bytes) const {
 165   // Determine if we need to generate a stack overflow check.
 166   // Do it if the method is not a stub function and
 167   // has java calls or has frame size > vm_page_size/8.
 168   return (UseStackBanging && stub_function() == NULL &&
 169           (has_java_calls() || frame_size_in_bytes > os::vm_page_size()>>3));
 170 }
 171 
 172 bool Compile::need_register_stack_bang() const {
 173   // Determine if we need to generate a register stack overflow check.
 174   // This is only used on architectures which have split register
 175   // and memory stacks (ie. IA64).
 176   // Bang if the method is not a stub function and has java calls
 177   return (stub_function() == NULL && has_java_calls());
 178 }
 179 
 180 # ifdef ENABLE_ZAP_DEAD_LOCALS
 181 
 182 
 183 // In order to catch compiler oop-map bugs, we have implemented
 184 // a debugging mode called ZapDeadCompilerLocals.
 185 // This mode causes the compiler to insert a call to a runtime routine,
 186 // "zap_dead_locals", right before each place in compiled code
 187 // that could potentially be a gc-point (i.e., a safepoint or oop map point).
 188 // The runtime routine checks that locations mapped as oops are really
 189 // oops, that locations mapped as values do not look like oops,
 190 // and that locations mapped as dead are not used later
 191 // (by zapping them to an invalid address).
 192 
 193 int Compile::_CompiledZap_count = 0;
 194 
 195 void Compile::Insert_zap_nodes() {
 196   bool skip = false;
 197 
 198 
 199   // Dink with static counts because code code without the extra
 200   // runtime calls is MUCH faster for debugging purposes
 201 
 202        if ( CompileZapFirst  ==  0  ) ; // nothing special
 203   else if ( CompileZapFirst  >  CompiledZap_count() )  skip = true;
 204   else if ( CompileZapFirst  == CompiledZap_count() )
 205     warning("starting zap compilation after skipping");
 206 
 207        if ( CompileZapLast  ==  -1  ) ; // nothing special
 208   else if ( CompileZapLast  <   CompiledZap_count() )  skip = true;
 209   else if ( CompileZapLast  ==  CompiledZap_count() )
 210     warning("about to compile last zap");
 211 
 212   ++_CompiledZap_count; // counts skipped zaps, too
 213 
 214   if ( skip )  return;
 215 
 216 
 217   if ( _method == NULL )
 218     return; // no safepoints/oopmaps emitted for calls in stubs,so we don't care
 219 
 220   // Insert call to zap runtime stub before every node with an oop map
 221   for( uint i=0; i<_cfg->number_of_blocks(); i++ ) {
 222     Block *b = _cfg->get_block(i);
 223     for ( uint j = 0;  j < b->number_of_nodes();  ++j ) {
 224       Node *n = b->get_node(j);
 225 
 226       // Determining if we should insert a zap-a-lot node in output.
 227       // We do that for all nodes that has oopmap info, except for calls
 228       // to allocation.  Calls to allocation passes in the old top-of-eden pointer
 229       // and expect the C code to reset it.  Hence, there can be no safepoints between
 230       // the inlined-allocation and the call to new_Java, etc.
 231       // We also cannot zap monitor calls, as they must hold the microlock
 232       // during the call to Zap, which also wants to grab the microlock.
 233       bool insert = n->is_MachSafePoint() && (n->as_MachSafePoint()->oop_map() != NULL);
 234       if ( insert ) { // it is MachSafePoint
 235         if ( !n->is_MachCall() ) {
 236           insert = false;
 237         } else if ( n->is_MachCall() ) {
 238           MachCallNode* call = n->as_MachCall();
 239           if (call->entry_point() == OptoRuntime::new_instance_Java() ||
 240               call->entry_point() == OptoRuntime::new_array_Java() ||
 241               call->entry_point() == OptoRuntime::multianewarray2_Java() ||
 242               call->entry_point() == OptoRuntime::multianewarray3_Java() ||
 243               call->entry_point() == OptoRuntime::multianewarray4_Java() ||
 244               call->entry_point() == OptoRuntime::multianewarray5_Java() ||
 245               call->entry_point() == OptoRuntime::slow_arraycopy_Java() ||
 246               call->entry_point() == OptoRuntime::complete_monitor_locking_Java()
 247               ) {
 248             insert = false;
 249           }
 250         }
 251         if (insert) {
 252           Node *zap = call_zap_node(n->as_MachSafePoint(), i);
 253           b->insert_node(zap, j);
 254           _cfg->map_node_to_block(zap, b);
 255           ++j;
 256         }
 257       }
 258     }
 259   }
 260 }
 261 
 262 
 263 Node* Compile::call_zap_node(MachSafePointNode* node_to_check, int block_no) {
 264   const TypeFunc *tf = OptoRuntime::zap_dead_locals_Type();
 265   CallStaticJavaNode* ideal_node =
 266     new (this) CallStaticJavaNode( tf,
 267          OptoRuntime::zap_dead_locals_stub(_method->flags().is_native()),
 268                        "call zap dead locals stub", 0, TypePtr::BOTTOM);
 269   // We need to copy the OopMap from the site we're zapping at.
 270   // We have to make a copy, because the zap site might not be
 271   // a call site, and zap_dead is a call site.
 272   OopMap* clone = node_to_check->oop_map()->deep_copy();
 273 
 274   // Add the cloned OopMap to the zap node
 275   ideal_node->set_oop_map(clone);
 276   return _matcher->match_sfpt(ideal_node);
 277 }
 278 
 279 bool Compile::is_node_getting_a_safepoint( Node* n) {
 280   // This code duplicates the logic prior to the call of add_safepoint
 281   // below in this file.
 282   if( n->is_MachSafePoint() ) return true;
 283   return false;
 284 }
 285 
 286 # endif // ENABLE_ZAP_DEAD_LOCALS
 287 
 288 // Compute the size of first NumberOfLoopInstrToAlign instructions at the top
 289 // of a loop. When aligning a loop we need to provide enough instructions
 290 // in cpu's fetch buffer to feed decoders. The loop alignment could be
 291 // avoided if we have enough instructions in fetch buffer at the head of a loop.
 292 // By default, the size is set to 999999 by Block's constructor so that
 293 // a loop will be aligned if the size is not reset here.
 294 //
 295 // Note: Mach instructions could contain several HW instructions
 296 // so the size is estimated only.
 297 //
 298 void Compile::compute_loop_first_inst_sizes() {
 299   // The next condition is used to gate the loop alignment optimization.
 300   // Don't aligned a loop if there are enough instructions at the head of a loop
 301   // or alignment padding is larger then MaxLoopPad. By default, MaxLoopPad
 302   // is equal to OptoLoopAlignment-1 except on new Intel cpus, where it is
 303   // equal to 11 bytes which is the largest address NOP instruction.
 304   if (MaxLoopPad < OptoLoopAlignment - 1) {
 305     uint last_block = _cfg->number_of_blocks() - 1;
 306     for (uint i = 1; i <= last_block; i++) {
 307       Block* block = _cfg->get_block(i);
 308       // Check the first loop's block which requires an alignment.
 309       if (block->loop_alignment() > (uint)relocInfo::addr_unit()) {
 310         uint sum_size = 0;
 311         uint inst_cnt = NumberOfLoopInstrToAlign;
 312         inst_cnt = block->compute_first_inst_size(sum_size, inst_cnt, _regalloc);
 313 
 314         // Check subsequent fallthrough blocks if the loop's first
 315         // block(s) does not have enough instructions.
 316         Block *nb = block;
 317         while(inst_cnt > 0 &&
 318               i < last_block &&
 319               !_cfg->get_block(i + 1)->has_loop_alignment() &&
 320               !nb->has_successor(block)) {
 321           i++;
 322           nb = _cfg->get_block(i);
 323           inst_cnt  = nb->compute_first_inst_size(sum_size, inst_cnt, _regalloc);
 324         } // while( inst_cnt > 0 && i < last_block  )
 325 
 326         block->set_first_inst_size(sum_size);
 327       } // f( b->head()->is_Loop() )
 328     } // for( i <= last_block )
 329   } // if( MaxLoopPad < OptoLoopAlignment-1 )
 330 }
 331 
 332 // The architecture description provides short branch variants for some long
 333 // branch instructions. Replace eligible long branches with short branches.
 334 void Compile::shorten_branches(uint* blk_starts, int& code_size, int& reloc_size, int& stub_size) {
 335   // Compute size of each block, method size, and relocation information size
 336   uint nblocks  = _cfg->number_of_blocks();
 337 
 338   uint*      jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
 339   uint*      jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
 340   int*       jmp_nidx   = NEW_RESOURCE_ARRAY(int ,nblocks);
 341 
 342   // Collect worst case block paddings
 343   int* block_worst_case_pad = NEW_RESOURCE_ARRAY(int, nblocks);
 344   memset(block_worst_case_pad, 0, nblocks * sizeof(int));
 345 
 346   DEBUG_ONLY( uint *jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks); )
 347   DEBUG_ONLY( uint *jmp_rule = NEW_RESOURCE_ARRAY(uint,nblocks); )
 348 
 349   bool has_short_branch_candidate = false;
 350 
 351   // Initialize the sizes to 0
 352   code_size  = 0;          // Size in bytes of generated code
 353   stub_size  = 0;          // Size in bytes of all stub entries
 354   // Size in bytes of all relocation entries, including those in local stubs.
 355   // Start with 2-bytes of reloc info for the unvalidated entry point
 356   reloc_size = 1;          // Number of relocation entries
 357 
 358   // Make three passes.  The first computes pessimistic blk_starts,
 359   // relative jmp_offset and reloc_size information.  The second performs
 360   // short branch substitution using the pessimistic sizing.  The
 361   // third inserts nops where needed.
 362 
 363   // Step one, perform a pessimistic sizing pass.
 364   uint last_call_adr = max_uint;
 365   uint last_avoid_back_to_back_adr = max_uint;
 366   uint nop_size = (new (this) MachNopNode())->size(_regalloc);
 367   for (uint i = 0; i < nblocks; i++) { // For all blocks
 368     Block* block = _cfg->get_block(i);
 369 
 370     // During short branch replacement, we store the relative (to blk_starts)
 371     // offset of jump in jmp_offset, rather than the absolute offset of jump.
 372     // This is so that we do not need to recompute sizes of all nodes when
 373     // we compute correct blk_starts in our next sizing pass.
 374     jmp_offset[i] = 0;
 375     jmp_size[i]   = 0;
 376     jmp_nidx[i]   = -1;
 377     DEBUG_ONLY( jmp_target[i] = 0; )
 378     DEBUG_ONLY( jmp_rule[i]   = 0; )
 379 
 380     // Sum all instruction sizes to compute block size
 381     uint last_inst = block->number_of_nodes();
 382     uint blk_size = 0;
 383     for (uint j = 0; j < last_inst; j++) {
 384       Node* nj = block->get_node(j);
 385       // Handle machine instruction nodes
 386       if (nj->is_Mach()) {
 387         MachNode *mach = nj->as_Mach();
 388         blk_size += (mach->alignment_required() - 1) * relocInfo::addr_unit(); // assume worst case padding
 389         reloc_size += mach->reloc();
 390         if (mach->is_MachCall()) {
 391           // add size information for trampoline stub
 392           // class CallStubImpl is platform-specific and defined in the *.ad files.
 393           stub_size  += CallStubImpl::size_call_trampoline();
 394           reloc_size += CallStubImpl::reloc_call_trampoline();
 395 
 396           MachCallNode *mcall = mach->as_MachCall();
 397           // This destination address is NOT PC-relative
 398 
 399           mcall->method_set((intptr_t)mcall->entry_point());
 400 
 401           if (mcall->is_MachCallJava() && mcall->as_MachCallJava()->_method) {
 402             stub_size  += CompiledStaticCall::to_interp_stub_size();
 403             reloc_size += CompiledStaticCall::reloc_to_interp_stub();
 404           }
 405         } else if (mach->is_MachSafePoint()) {
 406           // If call/safepoint are adjacent, account for possible
 407           // nop to disambiguate the two safepoints.
 408           // ScheduleAndBundle() can rearrange nodes in a block,
 409           // check for all offsets inside this block.
 410           if (last_call_adr >= blk_starts[i]) {
 411             blk_size += nop_size;
 412           }
 413         }
 414         if (mach->avoid_back_to_back()) {
 415           // Nop is inserted between "avoid back to back" instructions.
 416           // ScheduleAndBundle() can rearrange nodes in a block,
 417           // check for all offsets inside this block.
 418           if (last_avoid_back_to_back_adr >= blk_starts[i]) {
 419             blk_size += nop_size;
 420           }
 421         }
 422         if (mach->may_be_short_branch()) {
 423           if (!nj->is_MachBranch()) {
 424 #ifndef PRODUCT
 425             nj->dump(3);
 426 #endif
 427             Unimplemented();
 428           }
 429           assert(jmp_nidx[i] == -1, "block should have only one branch");
 430           jmp_offset[i] = blk_size;
 431           jmp_size[i]   = nj->size(_regalloc);
 432           jmp_nidx[i]   = j;
 433           has_short_branch_candidate = true;
 434         }
 435       }
 436       blk_size += nj->size(_regalloc);
 437       // Remember end of call offset
 438       if (nj->is_MachCall() && !nj->is_MachCallLeaf()) {
 439         last_call_adr = blk_starts[i]+blk_size;
 440       }
 441       // Remember end of avoid_back_to_back offset
 442       if (nj->is_Mach() && nj->as_Mach()->avoid_back_to_back()) {
 443         last_avoid_back_to_back_adr = blk_starts[i]+blk_size;
 444       }
 445     }
 446 
 447     // When the next block starts a loop, we may insert pad NOP
 448     // instructions.  Since we cannot know our future alignment,
 449     // assume the worst.
 450     if (i < nblocks - 1) {
 451       Block* nb = _cfg->get_block(i + 1);
 452       int max_loop_pad = nb->code_alignment()-relocInfo::addr_unit();
 453       if (max_loop_pad > 0) {
 454         assert(is_power_of_2(max_loop_pad+relocInfo::addr_unit()), "");
 455         // Adjust last_call_adr and/or last_avoid_back_to_back_adr.
 456         // If either is the last instruction in this block, bump by
 457         // max_loop_pad in lock-step with blk_size, so sizing
 458         // calculations in subsequent blocks still can conservatively
 459         // detect that it may the last instruction in this block.
 460         if (last_call_adr == blk_starts[i]+blk_size) {
 461           last_call_adr += max_loop_pad;
 462         }
 463         if (last_avoid_back_to_back_adr == blk_starts[i]+blk_size) {
 464           last_avoid_back_to_back_adr += max_loop_pad;
 465         }
 466         blk_size += max_loop_pad;
 467         block_worst_case_pad[i + 1] = max_loop_pad;
 468       }
 469     }
 470 
 471     // Save block size; update total method size
 472     blk_starts[i+1] = blk_starts[i]+blk_size;
 473   }
 474 
 475   // Step two, replace eligible long jumps.
 476   bool progress = true;
 477   uint last_may_be_short_branch_adr = max_uint;
 478   while (has_short_branch_candidate && progress) {
 479     progress = false;
 480     has_short_branch_candidate = false;
 481     int adjust_block_start = 0;
 482     for (uint i = 0; i < nblocks; i++) {
 483       Block* block = _cfg->get_block(i);
 484       int idx = jmp_nidx[i];
 485       MachNode* mach = (idx == -1) ? NULL: block->get_node(idx)->as_Mach();
 486       if (mach != NULL && mach->may_be_short_branch()) {
 487 #ifdef ASSERT
 488         assert(jmp_size[i] > 0 && mach->is_MachBranch(), "sanity");
 489         int j;
 490         // Find the branch; ignore trailing NOPs.
 491         for (j = block->number_of_nodes()-1; j>=0; j--) {
 492           Node* n = block->get_node(j);
 493           if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con)
 494             break;
 495         }
 496         assert(j >= 0 && j == idx && block->get_node(j) == (Node*)mach, "sanity");
 497 #endif
 498         int br_size = jmp_size[i];
 499         int br_offs = blk_starts[i] + jmp_offset[i];
 500 
 501         // This requires the TRUE branch target be in succs[0]
 502         uint bnum = block->non_connector_successor(0)->_pre_order;
 503         int offset = blk_starts[bnum] - br_offs;
 504         if (bnum > i) { // adjust following block's offset
 505           offset -= adjust_block_start;
 506         }
 507 
 508         // This block can be a loop header, account for the padding
 509         // in the previous block.
 510         int block_padding = block_worst_case_pad[i];
 511         assert(i == 0 || block_padding == 0 || br_offs >= block_padding, "Should have at least a padding on top");
 512         // In the following code a nop could be inserted before
 513         // the branch which will increase the backward distance.
 514         bool needs_padding = ((uint)(br_offs - block_padding) == last_may_be_short_branch_adr);
 515         assert(!needs_padding || jmp_offset[i] == 0, "padding only branches at the beginning of block");
 516 
 517         if (needs_padding && offset <= 0)
 518           offset -= nop_size;
 519 
 520         if (_matcher->is_short_branch_offset(mach->rule(), br_size, offset)) {
 521           // We've got a winner.  Replace this branch.
 522           MachNode* replacement = mach->as_MachBranch()->short_branch_version(this);
 523 
 524           // Update the jmp_size.
 525           int new_size = replacement->size(_regalloc);
 526           int diff     = br_size - new_size;
 527           assert(diff >= (int)nop_size, "short_branch size should be smaller");
 528           // Conservatively take into accound padding between
 529           // avoid_back_to_back branches. Previous branch could be
 530           // converted into avoid_back_to_back branch during next
 531           // rounds.
 532           if (needs_padding && replacement->avoid_back_to_back()) {
 533             jmp_offset[i] += nop_size;
 534             diff -= nop_size;
 535           }
 536           adjust_block_start += diff;
 537           block->map_node(replacement, idx);
 538           mach->subsume_by(replacement, C);
 539           mach = replacement;
 540           progress = true;
 541 
 542           jmp_size[i] = new_size;
 543           DEBUG_ONLY( jmp_target[i] = bnum; );
 544           DEBUG_ONLY( jmp_rule[i] = mach->rule(); );
 545         } else {
 546           // The jump distance is not short, try again during next iteration.
 547           has_short_branch_candidate = true;
 548         }
 549       } // (mach->may_be_short_branch())
 550       if (mach != NULL && (mach->may_be_short_branch() ||
 551                            mach->avoid_back_to_back())) {
 552         last_may_be_short_branch_adr = blk_starts[i] + jmp_offset[i] + jmp_size[i];
 553       }
 554       blk_starts[i+1] -= adjust_block_start;
 555     }
 556   }
 557 
 558 #ifdef ASSERT
 559   for (uint i = 0; i < nblocks; i++) { // For all blocks
 560     if (jmp_target[i] != 0) {
 561       int br_size = jmp_size[i];
 562       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
 563       if (!_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
 564         tty->print_cr("target (%d) - jmp_offset(%d) = offset (%d), jump_size(%d), jmp_block B%d, target_block B%d", blk_starts[jmp_target[i]], blk_starts[i] + jmp_offset[i], offset, br_size, i, jmp_target[i]);
 565       }
 566       assert(_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset), "Displacement too large for short jmp");
 567     }
 568   }
 569 #endif
 570 
 571   // Step 3, compute the offsets of all blocks, will be done in fill_buffer()
 572   // after ScheduleAndBundle().
 573 
 574   // ------------------
 575   // Compute size for code buffer
 576   code_size = blk_starts[nblocks];
 577 
 578   // Relocation records
 579   reloc_size += 1;              // Relo entry for exception handler
 580 
 581   // Adjust reloc_size to number of record of relocation info
 582   // Min is 2 bytes, max is probably 6 or 8, with a tax up to 25% for
 583   // a relocation index.
 584   // The CodeBuffer will expand the locs array if this estimate is too low.
 585   reloc_size *= 10 / sizeof(relocInfo);
 586 }
 587 
 588 //------------------------------FillLocArray-----------------------------------
 589 // Create a bit of debug info and append it to the array.  The mapping is from
 590 // Java local or expression stack to constant, register or stack-slot.  For
 591 // doubles, insert 2 mappings and return 1 (to tell the caller that the next
 592 // entry has been taken care of and caller should skip it).
 593 static LocationValue *new_loc_value( PhaseRegAlloc *ra, OptoReg::Name regnum, Location::Type l_type ) {
 594   // This should never have accepted Bad before
 595   assert(OptoReg::is_valid(regnum), "location must be valid");
 596   return (OptoReg::is_reg(regnum))
 597     ? new LocationValue(Location::new_reg_loc(l_type, OptoReg::as_VMReg(regnum)) )
 598     : new LocationValue(Location::new_stk_loc(l_type,  ra->reg2offset(regnum)));
 599 }
 600 
 601 
 602 ObjectValue*
 603 Compile::sv_for_node_id(GrowableArray<ScopeValue*> *objs, int id) {
 604   for (int i = 0; i < objs->length(); i++) {
 605     assert(objs->at(i)->is_object(), "corrupt object cache");
 606     ObjectValue* sv = (ObjectValue*) objs->at(i);
 607     if (sv->id() == id) {
 608       return sv;
 609     }
 610   }
 611   // Otherwise..
 612   return NULL;
 613 }
 614 
 615 void Compile::set_sv_for_object_node(GrowableArray<ScopeValue*> *objs,
 616                                      ObjectValue* sv ) {
 617   assert(sv_for_node_id(objs, sv->id()) == NULL, "Precondition");
 618   objs->append(sv);
 619 }
 620 
 621 
 622 void Compile::FillLocArray( int idx, MachSafePointNode* sfpt, Node *local,
 623                             GrowableArray<ScopeValue*> *array,
 624                             GrowableArray<ScopeValue*> *objs ) {
 625   assert( local, "use _top instead of null" );
 626   if (array->length() != idx) {
 627     assert(array->length() == idx + 1, "Unexpected array count");
 628     // Old functionality:
 629     //   return
 630     // New functionality:
 631     //   Assert if the local is not top. In product mode let the new node
 632     //   override the old entry.
 633     assert(local == top(), "LocArray collision");
 634     if (local == top()) {
 635       return;
 636     }
 637     array->pop();
 638   }
 639   const Type *t = local->bottom_type();
 640 
 641   // Is it a safepoint scalar object node?
 642   if (local->is_SafePointScalarObject()) {
 643     SafePointScalarObjectNode* spobj = local->as_SafePointScalarObject();
 644 
 645     ObjectValue* sv = Compile::sv_for_node_id(objs, spobj->_idx);
 646     if (sv == NULL) {
 647       ciKlass* cik = t->is_oopptr()->klass();
 648       assert(cik->is_instance_klass() ||
 649              cik->is_array_klass(), "Not supported allocation.");
 650       sv = new ObjectValue(spobj->_idx,
 651                            new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()));
 652       Compile::set_sv_for_object_node(objs, sv);
 653 
 654       uint first_ind = spobj->first_index(sfpt->jvms());
 655       for (uint i = 0; i < spobj->n_fields(); i++) {
 656         Node* fld_node = sfpt->in(first_ind+i);
 657         (void)FillLocArray(sv->field_values()->length(), sfpt, fld_node, sv->field_values(), objs);
 658       }
 659     }
 660     array->append(sv);
 661     return;
 662   }
 663 
 664   // Grab the register number for the local
 665   OptoReg::Name regnum = _regalloc->get_reg_first(local);
 666   if( OptoReg::is_valid(regnum) ) {// Got a register/stack?
 667     // Record the double as two float registers.
 668     // The register mask for such a value always specifies two adjacent
 669     // float registers, with the lower register number even.
 670     // Normally, the allocation of high and low words to these registers
 671     // is irrelevant, because nearly all operations on register pairs
 672     // (e.g., StoreD) treat them as a single unit.
 673     // Here, we assume in addition that the words in these two registers
 674     // stored "naturally" (by operations like StoreD and double stores
 675     // within the interpreter) such that the lower-numbered register
 676     // is written to the lower memory address.  This may seem like
 677     // a machine dependency, but it is not--it is a requirement on
 678     // the author of the <arch>.ad file to ensure that, for every
 679     // even/odd double-register pair to which a double may be allocated,
 680     // the word in the even single-register is stored to the first
 681     // memory word.  (Note that register numbers are completely
 682     // arbitrary, and are not tied to any machine-level encodings.)
 683 #ifdef _LP64
 684     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon ) {
 685       array->append(new ConstantIntValue(0));
 686       array->append(new_loc_value( _regalloc, regnum, Location::dbl ));
 687     } else if ( t->base() == Type::Long ) {
 688       array->append(new ConstantIntValue(0));
 689       array->append(new_loc_value( _regalloc, regnum, Location::lng ));
 690     } else if ( t->base() == Type::RawPtr ) {
 691       // jsr/ret return address which must be restored into a the full
 692       // width 64-bit stack slot.
 693       array->append(new_loc_value( _regalloc, regnum, Location::lng ));
 694     }
 695 #else //_LP64
 696 #ifdef SPARC
 697     if (t->base() == Type::Long && OptoReg::is_reg(regnum)) {
 698       // For SPARC we have to swap high and low words for
 699       // long values stored in a single-register (g0-g7).
 700       array->append(new_loc_value( _regalloc,              regnum   , Location::normal ));
 701       array->append(new_loc_value( _regalloc, OptoReg::add(regnum,1), Location::normal ));
 702     } else
 703 #endif //SPARC
 704     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon || t->base() == Type::Long ) {
 705       // Repack the double/long as two jints.
 706       // The convention the interpreter uses is that the second local
 707       // holds the first raw word of the native double representation.
 708       // This is actually reasonable, since locals and stack arrays
 709       // grow downwards in all implementations.
 710       // (If, on some machine, the interpreter's Java locals or stack
 711       // were to grow upwards, the embedded doubles would be word-swapped.)
 712       array->append(new_loc_value( _regalloc, OptoReg::add(regnum,1), Location::normal ));
 713       array->append(new_loc_value( _regalloc,              regnum   , Location::normal ));
 714     }
 715 #endif //_LP64
 716     else if( (t->base() == Type::FloatBot || t->base() == Type::FloatCon) &&
 717                OptoReg::is_reg(regnum) ) {
 718       array->append(new_loc_value( _regalloc, regnum, Matcher::float_in_double()
 719                                    ? Location::float_in_dbl : Location::normal ));
 720     } else if( t->base() == Type::Int && OptoReg::is_reg(regnum) ) {
 721       array->append(new_loc_value( _regalloc, regnum, Matcher::int_in_long
 722                                    ? Location::int_in_long : Location::normal ));
 723     } else if( t->base() == Type::NarrowOop ) {
 724       array->append(new_loc_value( _regalloc, regnum, Location::narrowoop ));
 725     } else {
 726       array->append(new_loc_value( _regalloc, regnum, _regalloc->is_oop(local) ? Location::oop : Location::normal ));
 727     }
 728     return;
 729   }
 730 
 731   // No register.  It must be constant data.
 732   switch (t->base()) {
 733   case Type::Half:              // Second half of a double
 734     ShouldNotReachHere();       // Caller should skip 2nd halves
 735     break;
 736   case Type::AnyPtr:
 737     array->append(new ConstantOopWriteValue(NULL));
 738     break;
 739   case Type::AryPtr:
 740   case Type::InstPtr:          // fall through
 741     array->append(new ConstantOopWriteValue(t->isa_oopptr()->const_oop()->constant_encoding()));
 742     break;
 743   case Type::NarrowOop:
 744     if (t == TypeNarrowOop::NULL_PTR) {
 745       array->append(new ConstantOopWriteValue(NULL));
 746     } else {
 747       array->append(new ConstantOopWriteValue(t->make_ptr()->isa_oopptr()->const_oop()->constant_encoding()));
 748     }
 749     break;
 750   case Type::Int:
 751     array->append(new ConstantIntValue(t->is_int()->get_con()));
 752     break;
 753   case Type::RawPtr:
 754     // A return address (T_ADDRESS).
 755     assert((intptr_t)t->is_ptr()->get_con() < (intptr_t)0x10000, "must be a valid BCI");
 756 #ifdef _LP64
 757     // Must be restored to the full-width 64-bit stack slot.
 758     array->append(new ConstantLongValue(t->is_ptr()->get_con()));
 759 #else
 760     array->append(new ConstantIntValue(t->is_ptr()->get_con()));
 761 #endif
 762     break;
 763   case Type::FloatCon: {
 764     float f = t->is_float_constant()->getf();
 765     array->append(new ConstantIntValue(jint_cast(f)));
 766     break;
 767   }
 768   case Type::DoubleCon: {
 769     jdouble d = t->is_double_constant()->getd();
 770 #ifdef _LP64
 771     array->append(new ConstantIntValue(0));
 772     array->append(new ConstantDoubleValue(d));
 773 #else
 774     // Repack the double as two jints.
 775     // The convention the interpreter uses is that the second local
 776     // holds the first raw word of the native double representation.
 777     // This is actually reasonable, since locals and stack arrays
 778     // grow downwards in all implementations.
 779     // (If, on some machine, the interpreter's Java locals or stack
 780     // were to grow upwards, the embedded doubles would be word-swapped.)
 781     jint   *dp = (jint*)&d;
 782     array->append(new ConstantIntValue(dp[1]));
 783     array->append(new ConstantIntValue(dp[0]));
 784 #endif
 785     break;
 786   }
 787   case Type::Long: {
 788     jlong d = t->is_long()->get_con();
 789 #ifdef _LP64
 790     array->append(new ConstantIntValue(0));
 791     array->append(new ConstantLongValue(d));
 792 #else
 793     // Repack the long as two jints.
 794     // The convention the interpreter uses is that the second local
 795     // holds the first raw word of the native double representation.
 796     // This is actually reasonable, since locals and stack arrays
 797     // grow downwards in all implementations.
 798     // (If, on some machine, the interpreter's Java locals or stack
 799     // were to grow upwards, the embedded doubles would be word-swapped.)
 800     jint *dp = (jint*)&d;
 801     array->append(new ConstantIntValue(dp[1]));
 802     array->append(new ConstantIntValue(dp[0]));
 803 #endif
 804     break;
 805   }
 806   case Type::Top:               // Add an illegal value here
 807     array->append(new LocationValue(Location()));
 808     break;
 809   default:
 810     ShouldNotReachHere();
 811     break;
 812   }
 813 }
 814 
 815 // Determine if this node starts a bundle
 816 bool Compile::starts_bundle(const Node *n) const {
 817   return (_node_bundling_limit > n->_idx &&
 818           _node_bundling_base[n->_idx].starts_bundle());
 819 }
 820 
 821 //--------------------------Process_OopMap_Node--------------------------------
 822 void Compile::Process_OopMap_Node(MachNode *mach, int current_offset) {
 823 
 824   // Handle special safepoint nodes for synchronization
 825   MachSafePointNode *sfn   = mach->as_MachSafePoint();
 826   MachCallNode      *mcall;
 827 
 828 #ifdef ENABLE_ZAP_DEAD_LOCALS
 829   assert( is_node_getting_a_safepoint(mach),  "logic does not match; false negative");
 830 #endif
 831 
 832   int safepoint_pc_offset = current_offset;
 833   bool is_method_handle_invoke = false;
 834   bool return_oop = false;
 835 
 836   // Add the safepoint in the DebugInfoRecorder
 837   if( !mach->is_MachCall() ) {
 838     mcall = NULL;
 839     debug_info()->add_safepoint(safepoint_pc_offset, sfn->_oop_map);
 840   } else {
 841     mcall = mach->as_MachCall();
 842 
 843     // Is the call a MethodHandle call?
 844     if (mcall->is_MachCallJava()) {
 845       if (mcall->as_MachCallJava()->_method_handle_invoke) {
 846         assert(has_method_handle_invokes(), "must have been set during call generation");
 847         is_method_handle_invoke = true;
 848       }
 849     }
 850 
 851     // Check if a call returns an object.
 852     if (mcall->return_value_is_used() &&
 853         mcall->tf()->range()->field_at(TypeFunc::Parms)->isa_ptr()) {
 854       return_oop = true;
 855     }
 856     safepoint_pc_offset += mcall->ret_addr_offset();
 857     debug_info()->add_safepoint(safepoint_pc_offset, mcall->_oop_map);
 858   }
 859 
 860   // Loop over the JVMState list to add scope information
 861   // Do not skip safepoints with a NULL method, they need monitor info
 862   JVMState* youngest_jvms = sfn->jvms();
 863   int max_depth = youngest_jvms->depth();
 864 
 865   // Allocate the object pool for scalar-replaced objects -- the map from
 866   // small-integer keys (which can be recorded in the local and ostack
 867   // arrays) to descriptions of the object state.
 868   GrowableArray<ScopeValue*> *objs = new GrowableArray<ScopeValue*>();
 869 
 870   // Visit scopes from oldest to youngest.
 871   for (int depth = 1; depth <= max_depth; depth++) {
 872     JVMState* jvms = youngest_jvms->of_depth(depth);
 873     int idx;
 874     ciMethod* method = jvms->has_method() ? jvms->method() : NULL;
 875     // Safepoints that do not have method() set only provide oop-map and monitor info
 876     // to support GC; these do not support deoptimization.
 877     int num_locs = (method == NULL) ? 0 : jvms->loc_size();
 878     int num_exps = (method == NULL) ? 0 : jvms->stk_size();
 879     int num_mon  = jvms->nof_monitors();
 880     assert(method == NULL || jvms->bci() < 0 || num_locs == method->max_locals(),
 881            "JVMS local count must match that of the method");
 882 
 883     // Add Local and Expression Stack Information
 884 
 885     // Insert locals into the locarray
 886     GrowableArray<ScopeValue*> *locarray = new GrowableArray<ScopeValue*>(num_locs);
 887     for( idx = 0; idx < num_locs; idx++ ) {
 888       FillLocArray( idx, sfn, sfn->local(jvms, idx), locarray, objs );
 889     }
 890 
 891     // Insert expression stack entries into the exparray
 892     GrowableArray<ScopeValue*> *exparray = new GrowableArray<ScopeValue*>(num_exps);
 893     for( idx = 0; idx < num_exps; idx++ ) {
 894       FillLocArray( idx,  sfn, sfn->stack(jvms, idx), exparray, objs );
 895     }
 896 
 897     // Add in mappings of the monitors
 898     assert( !method ||
 899             !method->is_synchronized() ||
 900             method->is_native() ||
 901             num_mon > 0 ||
 902             !GenerateSynchronizationCode,
 903             "monitors must always exist for synchronized methods");
 904 
 905     // Build the growable array of ScopeValues for exp stack
 906     GrowableArray<MonitorValue*> *monarray = new GrowableArray<MonitorValue*>(num_mon);
 907 
 908     // Loop over monitors and insert into array
 909     for (idx = 0; idx < num_mon; idx++) {
 910       // Grab the node that defines this monitor
 911       Node* box_node = sfn->monitor_box(jvms, idx);
 912       Node* obj_node = sfn->monitor_obj(jvms, idx);
 913 
 914       // Create ScopeValue for object
 915       ScopeValue *scval = NULL;
 916 
 917       if (obj_node->is_SafePointScalarObject()) {
 918         SafePointScalarObjectNode* spobj = obj_node->as_SafePointScalarObject();
 919         scval = Compile::sv_for_node_id(objs, spobj->_idx);
 920         if (scval == NULL) {
 921           const Type *t = spobj->bottom_type();
 922           ciKlass* cik = t->is_oopptr()->klass();
 923           assert(cik->is_instance_klass() ||
 924                  cik->is_array_klass(), "Not supported allocation.");
 925           ObjectValue* sv = new ObjectValue(spobj->_idx,
 926                                             new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()));
 927           Compile::set_sv_for_object_node(objs, sv);
 928 
 929           uint first_ind = spobj->first_index(youngest_jvms);
 930           for (uint i = 0; i < spobj->n_fields(); i++) {
 931             Node* fld_node = sfn->in(first_ind+i);
 932             (void)FillLocArray(sv->field_values()->length(), sfn, fld_node, sv->field_values(), objs);
 933           }
 934           scval = sv;
 935         }
 936       } else if (!obj_node->is_Con()) {
 937         OptoReg::Name obj_reg = _regalloc->get_reg_first(obj_node);
 938         if( obj_node->bottom_type()->base() == Type::NarrowOop ) {
 939           scval = new_loc_value( _regalloc, obj_reg, Location::narrowoop );
 940         } else {
 941           scval = new_loc_value( _regalloc, obj_reg, Location::oop );
 942         }
 943       } else {
 944         const TypePtr *tp = obj_node->get_ptr_type();
 945         scval = new ConstantOopWriteValue(tp->is_oopptr()->const_oop()->constant_encoding());
 946       }
 947 
 948       OptoReg::Name box_reg = BoxLockNode::reg(box_node);
 949       Location basic_lock = Location::new_stk_loc(Location::normal,_regalloc->reg2offset(box_reg));
 950       bool eliminated = (box_node->is_BoxLock() && box_node->as_BoxLock()->is_eliminated());
 951       monarray->append(new MonitorValue(scval, basic_lock, eliminated));
 952     }
 953 
 954     // We dump the object pool first, since deoptimization reads it in first.
 955     debug_info()->dump_object_pool(objs);
 956 
 957     // Build first class objects to pass to scope
 958     DebugToken *locvals = debug_info()->create_scope_values(locarray);
 959     DebugToken *expvals = debug_info()->create_scope_values(exparray);
 960     DebugToken *monvals = debug_info()->create_monitor_values(monarray);
 961 
 962     // Make method available for all Safepoints
 963     ciMethod* scope_method = method ? method : _method;
 964     // Describe the scope here
 965     assert(jvms->bci() >= InvocationEntryBci && jvms->bci() <= 0x10000, "must be a valid or entry BCI");
 966     assert(!jvms->should_reexecute() || depth == max_depth, "reexecute allowed only for the youngest");
 967     // Now we can describe the scope.
 968     debug_info()->describe_scope(safepoint_pc_offset, scope_method, jvms->bci(), jvms->should_reexecute(), is_method_handle_invoke, return_oop, locvals, expvals, monvals);
 969   } // End jvms loop
 970 
 971   // Mark the end of the scope set.
 972   debug_info()->end_safepoint(safepoint_pc_offset);
 973 }
 974 
 975 
 976 
 977 // A simplified version of Process_OopMap_Node, to handle non-safepoints.
 978 class NonSafepointEmitter {
 979   Compile*  C;
 980   JVMState* _pending_jvms;
 981   int       _pending_offset;
 982 
 983   void emit_non_safepoint();
 984 
 985  public:
 986   NonSafepointEmitter(Compile* compile) {
 987     this->C = compile;
 988     _pending_jvms = NULL;
 989     _pending_offset = 0;
 990   }
 991 
 992   void observe_instruction(Node* n, int pc_offset) {
 993     if (!C->debug_info()->recording_non_safepoints())  return;
 994 
 995     Node_Notes* nn = C->node_notes_at(n->_idx);
 996     if (nn == NULL || nn->jvms() == NULL)  return;
 997     if (_pending_jvms != NULL &&
 998         _pending_jvms->same_calls_as(nn->jvms())) {
 999       // Repeated JVMS?  Stretch it up here.
1000       _pending_offset = pc_offset;
1001     } else {
1002       if (_pending_jvms != NULL &&
1003           _pending_offset < pc_offset) {
1004         emit_non_safepoint();
1005       }
1006       _pending_jvms = NULL;
1007       if (pc_offset > C->debug_info()->last_pc_offset()) {
1008         // This is the only way _pending_jvms can become non-NULL:
1009         _pending_jvms = nn->jvms();
1010         _pending_offset = pc_offset;
1011       }
1012     }
1013   }
1014 
1015   // Stay out of the way of real safepoints:
1016   void observe_safepoint(JVMState* jvms, int pc_offset) {
1017     if (_pending_jvms != NULL &&
1018         !_pending_jvms->same_calls_as(jvms) &&
1019         _pending_offset < pc_offset) {
1020       emit_non_safepoint();
1021     }
1022     _pending_jvms = NULL;
1023   }
1024 
1025   void flush_at_end() {
1026     if (_pending_jvms != NULL) {
1027       emit_non_safepoint();
1028     }
1029     _pending_jvms = NULL;
1030   }
1031 };
1032 
1033 void NonSafepointEmitter::emit_non_safepoint() {
1034   JVMState* youngest_jvms = _pending_jvms;
1035   int       pc_offset     = _pending_offset;
1036 
1037   // Clear it now:
1038   _pending_jvms = NULL;
1039 
1040   DebugInformationRecorder* debug_info = C->debug_info();
1041   assert(debug_info->recording_non_safepoints(), "sanity");
1042 
1043   debug_info->add_non_safepoint(pc_offset);
1044   int max_depth = youngest_jvms->depth();
1045 
1046   // Visit scopes from oldest to youngest.
1047   for (int depth = 1; depth <= max_depth; depth++) {
1048     JVMState* jvms = youngest_jvms->of_depth(depth);
1049     ciMethod* method = jvms->has_method() ? jvms->method() : NULL;
1050     assert(!jvms->should_reexecute() || depth==max_depth, "reexecute allowed only for the youngest");
1051     debug_info->describe_scope(pc_offset, method, jvms->bci(), jvms->should_reexecute());
1052   }
1053 
1054   // Mark the end of the scope set.
1055   debug_info->end_non_safepoint(pc_offset);
1056 }
1057 
1058 //------------------------------init_buffer------------------------------------
1059 CodeBuffer* Compile::init_buffer(uint* blk_starts) {
1060 
1061   // Set the initially allocated size
1062   int  code_req   = initial_code_capacity;
1063   int  locs_req   = initial_locs_capacity;
1064   int  stub_req   = TraceJumps ? initial_stub_capacity * 10 : initial_stub_capacity;
1065   int  const_req  = initial_const_capacity;
1066 
1067   int  pad_req    = NativeCall::instruction_size;
1068   // The extra spacing after the code is necessary on some platforms.
1069   // Sometimes we need to patch in a jump after the last instruction,
1070   // if the nmethod has been deoptimized.  (See 4932387, 4894843.)
1071 
1072   // Compute the byte offset where we can store the deopt pc.
1073   if (fixed_slots() != 0) {
1074     _orig_pc_slot_offset_in_bytes = _regalloc->reg2offset(OptoReg::stack2reg(_orig_pc_slot));
1075   }
1076 
1077   // Compute prolog code size
1078   _method_size = 0;
1079   _frame_slots = OptoReg::reg2stack(_matcher->_old_SP)+_regalloc->_framesize;
1080 #if defined(IA64) && !defined(AIX)
1081   if (save_argument_registers()) {
1082     // 4815101: this is a stub with implicit and unknown precision fp args.
1083     // The usual spill mechanism can only generate stfd's in this case, which
1084     // doesn't work if the fp reg to spill contains a single-precision denorm.
1085     // Instead, we hack around the normal spill mechanism using stfspill's and
1086     // ldffill's in the MachProlog and MachEpilog emit methods.  We allocate
1087     // space here for the fp arg regs (f8-f15) we're going to thusly spill.
1088     //
1089     // If we ever implement 16-byte 'registers' == stack slots, we can
1090     // get rid of this hack and have SpillCopy generate stfspill/ldffill
1091     // instead of stfd/stfs/ldfd/ldfs.
1092     _frame_slots += 8*(16/BytesPerInt);
1093   }
1094 #endif
1095   assert(_frame_slots >= 0 && _frame_slots < 1000000, "sanity check");
1096 
1097   if (has_mach_constant_base_node()) {
1098     uint add_size = 0;
1099     // Fill the constant table.
1100     // Note:  This must happen before shorten_branches.
1101     for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
1102       Block* b = _cfg->get_block(i);
1103 
1104       for (uint j = 0; j < b->number_of_nodes(); j++) {
1105         Node* n = b->get_node(j);
1106 
1107         // If the node is a MachConstantNode evaluate the constant
1108         // value section.
1109         if (n->is_MachConstant()) {
1110           MachConstantNode* machcon = n->as_MachConstant();
1111           machcon->eval_constant(C);
1112         } else if (n->is_Mach()) {
1113           // On Power there are more nodes that issue constants.
1114           add_size += (n->as_Mach()->ins_num_consts() * 8);
1115         }
1116       }
1117     }
1118 
1119     // Calculate the offsets of the constants and the size of the
1120     // constant table (including the padding to the next section).
1121     constant_table().calculate_offsets_and_size();
1122     const_req = constant_table().size() + add_size;
1123   }
1124 
1125   // Initialize the space for the BufferBlob used to find and verify
1126   // instruction size in MachNode::emit_size()
1127   init_scratch_buffer_blob(const_req);
1128   if (failing())  return NULL; // Out of memory
1129 
1130   // Pre-compute the length of blocks and replace
1131   // long branches with short if machine supports it.
1132   shorten_branches(blk_starts, code_req, locs_req, stub_req);
1133 
1134   // nmethod and CodeBuffer count stubs & constants as part of method's code.
1135   // class HandlerImpl is platform-specific and defined in the *.ad files.
1136   int exception_handler_req = HandlerImpl::size_exception_handler() + MAX_stubs_size; // add marginal slop for handler
1137   int deopt_handler_req     = HandlerImpl::size_deopt_handler()     + MAX_stubs_size; // add marginal slop for handler
1138   stub_req += MAX_stubs_size;   // ensure per-stub margin
1139   code_req += MAX_inst_size;    // ensure per-instruction margin
1140 
1141   if (StressCodeBuffers)
1142     code_req = const_req = stub_req = exception_handler_req = deopt_handler_req = 0x10;  // force expansion
1143 
1144   int total_req =
1145     const_req +
1146     code_req +
1147     pad_req +
1148     stub_req +
1149     exception_handler_req +
1150     deopt_handler_req;               // deopt handler
1151 
1152   if (has_method_handle_invokes())
1153     total_req += deopt_handler_req;  // deopt MH handler
1154 
1155   CodeBuffer* cb = code_buffer();
1156   cb->initialize(total_req, locs_req);
1157 
1158   // Have we run out of code space?
1159   if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1160     C->record_failure("CodeCache is full");
1161     return NULL;
1162   }
1163   // Configure the code buffer.
1164   cb->initialize_consts_size(const_req);
1165   cb->initialize_stubs_size(stub_req);
1166   cb->initialize_oop_recorder(env()->oop_recorder());
1167 
1168   // fill in the nop array for bundling computations
1169   MachNode *_nop_list[Bundle::_nop_count];
1170   Bundle::initialize_nops(_nop_list, this);
1171 
1172   return cb;
1173 }
1174 
1175 //------------------------------fill_buffer------------------------------------
1176 void Compile::fill_buffer(CodeBuffer* cb, uint* blk_starts) {
1177   // blk_starts[] contains offsets calculated during short branches processing,
1178   // offsets should not be increased during following steps.
1179 
1180   // Compute the size of first NumberOfLoopInstrToAlign instructions at head
1181   // of a loop. It is used to determine the padding for loop alignment.
1182   compute_loop_first_inst_sizes();
1183 
1184   // Create oopmap set.
1185   _oop_map_set = new OopMapSet();
1186 
1187   // !!!!! This preserves old handling of oopmaps for now
1188   debug_info()->set_oopmaps(_oop_map_set);
1189 
1190   uint nblocks  = _cfg->number_of_blocks();
1191   // Count and start of implicit null check instructions
1192   uint inct_cnt = 0;
1193   uint *inct_starts = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1194 
1195   // Count and start of calls
1196   uint *call_returns = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1197 
1198   uint  return_offset = 0;
1199   int nop_size = (new (this) MachNopNode())->size(_regalloc);
1200 
1201   int previous_offset = 0;
1202   int current_offset  = 0;
1203   int last_call_offset = -1;
1204   int last_avoid_back_to_back_offset = -1;
1205 #ifdef ASSERT
1206   uint* jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks);
1207   uint* jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
1208   uint* jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
1209   uint* jmp_rule   = NEW_RESOURCE_ARRAY(uint,nblocks);
1210 #endif
1211 
1212   // Create an array of unused labels, one for each basic block, if printing is enabled
1213 #ifndef PRODUCT
1214   int *node_offsets      = NULL;
1215   uint node_offset_limit = unique();
1216 
1217   if (print_assembly())
1218     node_offsets         = NEW_RESOURCE_ARRAY(int, node_offset_limit);
1219 #endif
1220 
1221   NonSafepointEmitter non_safepoints(this);  // emit non-safepoints lazily
1222 
1223   // Emit the constant table.
1224   if (has_mach_constant_base_node()) {
1225     constant_table().emit(*cb);
1226   }
1227 
1228   // Create an array of labels, one for each basic block
1229   Label *blk_labels = NEW_RESOURCE_ARRAY(Label, nblocks+1);
1230   for (uint i=0; i <= nblocks; i++) {
1231     blk_labels[i].init();
1232   }
1233 
1234   // ------------------
1235   // Now fill in the code buffer
1236   Node *delay_slot = NULL;
1237 
1238   for (uint i = 0; i < nblocks; i++) {
1239     Block* block = _cfg->get_block(i);
1240     Node* head = block->head();
1241 
1242     // If this block needs to start aligned (i.e, can be reached other
1243     // than by falling-thru from the previous block), then force the
1244     // start of a new bundle.
1245     if (Pipeline::requires_bundling() && starts_bundle(head)) {
1246       cb->flush_bundle(true);
1247     }
1248 
1249 #ifdef ASSERT
1250     if (!block->is_connector()) {
1251       stringStream st;
1252       block->dump_head(_cfg, &st);
1253       MacroAssembler(cb).block_comment(st.as_string());
1254     }
1255     jmp_target[i] = 0;
1256     jmp_offset[i] = 0;
1257     jmp_size[i]   = 0;
1258     jmp_rule[i]   = 0;
1259 #endif
1260     int blk_offset = current_offset;
1261 
1262     // Define the label at the beginning of the basic block
1263     MacroAssembler(cb).bind(blk_labels[block->_pre_order]);
1264 
1265     uint last_inst = block->number_of_nodes();
1266 
1267     // Emit block normally, except for last instruction.
1268     // Emit means "dump code bits into code buffer".
1269     for (uint j = 0; j<last_inst; j++) {
1270 
1271       // Get the node
1272       Node* n = block->get_node(j);
1273 
1274       // See if delay slots are supported
1275       if (valid_bundle_info(n) &&
1276           node_bundling(n)->used_in_unconditional_delay()) {
1277         assert(delay_slot == NULL, "no use of delay slot node");
1278         assert(n->size(_regalloc) == Pipeline::instr_unit_size(), "delay slot instruction wrong size");
1279 
1280         delay_slot = n;
1281         continue;
1282       }
1283 
1284       // If this starts a new instruction group, then flush the current one
1285       // (but allow split bundles)
1286       if (Pipeline::requires_bundling() && starts_bundle(n))
1287         cb->flush_bundle(false);
1288 
1289       // The following logic is duplicated in the code ifdeffed for
1290       // ENABLE_ZAP_DEAD_LOCALS which appears above in this file.  It
1291       // should be factored out.  Or maybe dispersed to the nodes?
1292 
1293       // Special handling for SafePoint/Call Nodes
1294       bool is_mcall = false;
1295       if (n->is_Mach()) {
1296         MachNode *mach = n->as_Mach();
1297         is_mcall = n->is_MachCall();
1298         bool is_sfn = n->is_MachSafePoint();
1299 
1300         // If this requires all previous instructions be flushed, then do so
1301         if (is_sfn || is_mcall || mach->alignment_required() != 1) {
1302           cb->flush_bundle(true);
1303           current_offset = cb->insts_size();
1304         }
1305 
1306         // A padding may be needed again since a previous instruction
1307         // could be moved to delay slot.
1308 
1309         // align the instruction if necessary
1310         int padding = mach->compute_padding(current_offset);
1311         // Make sure safepoint node for polling is distinct from a call's
1312         // return by adding a nop if needed.
1313         if (is_sfn && !is_mcall && padding == 0 && current_offset == last_call_offset) {
1314           padding = nop_size;
1315         }
1316         if (padding == 0 && mach->avoid_back_to_back() &&
1317             current_offset == last_avoid_back_to_back_offset) {
1318           // Avoid back to back some instructions.
1319           padding = nop_size;
1320         }
1321 
1322         if(padding > 0) {
1323           assert((padding % nop_size) == 0, "padding is not a multiple of NOP size");
1324           int nops_cnt = padding / nop_size;
1325           MachNode *nop = new (this) MachNopNode(nops_cnt);
1326           block->insert_node(nop, j++);
1327           last_inst++;
1328           _cfg->map_node_to_block(nop, block);
1329           nop->emit(*cb, _regalloc);
1330           cb->flush_bundle(true);
1331           current_offset = cb->insts_size();
1332         }
1333 
1334         // Remember the start of the last call in a basic block
1335         if (is_mcall) {
1336           MachCallNode *mcall = mach->as_MachCall();
1337 
1338           // This destination address is NOT PC-relative
1339           mcall->method_set((intptr_t)mcall->entry_point());
1340 
1341           // Save the return address
1342           call_returns[block->_pre_order] = current_offset + mcall->ret_addr_offset();
1343 
1344           if (mcall->is_MachCallLeaf()) {
1345             is_mcall = false;
1346             is_sfn = false;
1347           }
1348         }
1349 
1350         // sfn will be valid whenever mcall is valid now because of inheritance
1351         if (is_sfn || is_mcall) {
1352 
1353           // Handle special safepoint nodes for synchronization
1354           if (!is_mcall) {
1355             MachSafePointNode *sfn = mach->as_MachSafePoint();
1356             // !!!!! Stubs only need an oopmap right now, so bail out
1357             if (sfn->jvms()->method() == NULL) {
1358               // Write the oopmap directly to the code blob??!!
1359 #             ifdef ENABLE_ZAP_DEAD_LOCALS
1360               assert( !is_node_getting_a_safepoint(sfn),  "logic does not match; false positive");
1361 #             endif
1362               continue;
1363             }
1364           } // End synchronization
1365 
1366           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1367                                            current_offset);
1368           Process_OopMap_Node(mach, current_offset);
1369         } // End if safepoint
1370 
1371         // If this is a null check, then add the start of the previous instruction to the list
1372         else if( mach->is_MachNullCheck() ) {
1373           inct_starts[inct_cnt++] = previous_offset;
1374         }
1375 
1376         // If this is a branch, then fill in the label with the target BB's label
1377         else if (mach->is_MachBranch()) {
1378           // This requires the TRUE branch target be in succs[0]
1379           uint block_num = block->non_connector_successor(0)->_pre_order;
1380 
1381           // Try to replace long branch if delay slot is not used,
1382           // it is mostly for back branches since forward branch's
1383           // distance is not updated yet.
1384           bool delay_slot_is_used = valid_bundle_info(n) &&
1385                                     node_bundling(n)->use_unconditional_delay();
1386           if (!delay_slot_is_used && mach->may_be_short_branch()) {
1387            assert(delay_slot == NULL, "not expecting delay slot node");
1388            int br_size = n->size(_regalloc);
1389             int offset = blk_starts[block_num] - current_offset;
1390             if (block_num >= i) {
1391               // Current and following block's offset are not
1392               // finalized yet, adjust distance by the difference
1393               // between calculated and final offsets of current block.
1394               offset -= (blk_starts[i] - blk_offset);
1395             }
1396             // In the following code a nop could be inserted before
1397             // the branch which will increase the backward distance.
1398             bool needs_padding = (current_offset == last_avoid_back_to_back_offset);
1399             if (needs_padding && offset <= 0)
1400               offset -= nop_size;
1401 
1402             if (_matcher->is_short_branch_offset(mach->rule(), br_size, offset)) {
1403               // We've got a winner.  Replace this branch.
1404               MachNode* replacement = mach->as_MachBranch()->short_branch_version(this);
1405 
1406               // Update the jmp_size.
1407               int new_size = replacement->size(_regalloc);
1408               assert((br_size - new_size) >= (int)nop_size, "short_branch size should be smaller");
1409               // Insert padding between avoid_back_to_back branches.
1410               if (needs_padding && replacement->avoid_back_to_back()) {
1411                 MachNode *nop = new (this) MachNopNode();
1412                 block->insert_node(nop, j++);
1413                 _cfg->map_node_to_block(nop, block);
1414                 last_inst++;
1415                 nop->emit(*cb, _regalloc);
1416                 cb->flush_bundle(true);
1417                 current_offset = cb->insts_size();
1418               }
1419 #ifdef ASSERT
1420               jmp_target[i] = block_num;
1421               jmp_offset[i] = current_offset - blk_offset;
1422               jmp_size[i]   = new_size;
1423               jmp_rule[i]   = mach->rule();
1424 #endif
1425               block->map_node(replacement, j);
1426               mach->subsume_by(replacement, C);
1427               n    = replacement;
1428               mach = replacement;
1429             }
1430           }
1431           mach->as_MachBranch()->label_set( &blk_labels[block_num], block_num );
1432         } else if (mach->ideal_Opcode() == Op_Jump) {
1433           for (uint h = 0; h < block->_num_succs; h++) {
1434             Block* succs_block = block->_succs[h];
1435             for (uint j = 1; j < succs_block->num_preds(); j++) {
1436               Node* jpn = succs_block->pred(j);
1437               if (jpn->is_JumpProj() && jpn->in(0) == mach) {
1438                 uint block_num = succs_block->non_connector()->_pre_order;
1439                 Label *blkLabel = &blk_labels[block_num];
1440                 mach->add_case_label(jpn->as_JumpProj()->proj_no(), blkLabel);
1441               }
1442             }
1443           }
1444         }
1445 #ifdef ASSERT
1446         // Check that oop-store precedes the card-mark
1447         else if (mach->ideal_Opcode() == Op_StoreCM) {
1448           uint storeCM_idx = j;
1449           int count = 0;
1450           for (uint prec = mach->req(); prec < mach->len(); prec++) {
1451             Node *oop_store = mach->in(prec);  // Precedence edge
1452             if (oop_store == NULL) continue;
1453             count++;
1454             uint i4;
1455             for (i4 = 0; i4 < last_inst; ++i4) {
1456               if (block->get_node(i4) == oop_store) {
1457                 break;
1458               }
1459             }
1460             // Note: This test can provide a false failure if other precedence
1461             // edges have been added to the storeCMNode.
1462             assert(i4 == last_inst || i4 < storeCM_idx, "CM card-mark executes before oop-store");
1463           }
1464           assert(count > 0, "storeCM expects at least one precedence edge");
1465         }
1466 #endif
1467         else if (!n->is_Proj()) {
1468           // Remember the beginning of the previous instruction, in case
1469           // it's followed by a flag-kill and a null-check.  Happens on
1470           // Intel all the time, with add-to-memory kind of opcodes.
1471           previous_offset = current_offset;
1472         }
1473 
1474         // Not an else-if!
1475         // If this is a trap based cmp then add its offset to the list.
1476         if (mach->is_TrapBasedCheckNode()) {
1477           inct_starts[inct_cnt++] = current_offset;
1478         }
1479       }
1480 
1481       // Verify that there is sufficient space remaining
1482       cb->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
1483       if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1484         C->record_failure("CodeCache is full");
1485         return;
1486       }
1487 
1488       // Save the offset for the listing
1489 #ifndef PRODUCT
1490       if (node_offsets && n->_idx < node_offset_limit)
1491         node_offsets[n->_idx] = cb->insts_size();
1492 #endif
1493 
1494       // "Normal" instruction case
1495       DEBUG_ONLY( uint instr_offset = cb->insts_size(); )
1496       n->emit(*cb, _regalloc);
1497       current_offset  = cb->insts_size();
1498 
1499 #ifdef ASSERT
1500       if (n->size(_regalloc) < (current_offset-instr_offset)) {
1501         n->dump();
1502         assert(false, "wrong size of mach node");
1503       }
1504 #endif
1505       non_safepoints.observe_instruction(n, current_offset);
1506 
1507       // mcall is last "call" that can be a safepoint
1508       // record it so we can see if a poll will directly follow it
1509       // in which case we'll need a pad to make the PcDesc sites unique
1510       // see  5010568. This can be slightly inaccurate but conservative
1511       // in the case that return address is not actually at current_offset.
1512       // This is a small price to pay.
1513 
1514       if (is_mcall) {
1515         last_call_offset = current_offset;
1516       }
1517 
1518       if (n->is_Mach() && n->as_Mach()->avoid_back_to_back()) {
1519         // Avoid back to back some instructions.
1520         last_avoid_back_to_back_offset = current_offset;
1521       }
1522 
1523       // See if this instruction has a delay slot
1524       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
1525         assert(delay_slot != NULL, "expecting delay slot node");
1526 
1527         // Back up 1 instruction
1528         cb->set_insts_end(cb->insts_end() - Pipeline::instr_unit_size());
1529 
1530         // Save the offset for the listing
1531 #ifndef PRODUCT
1532         if (node_offsets && delay_slot->_idx < node_offset_limit)
1533           node_offsets[delay_slot->_idx] = cb->insts_size();
1534 #endif
1535 
1536         // Support a SafePoint in the delay slot
1537         if (delay_slot->is_MachSafePoint()) {
1538           MachNode *mach = delay_slot->as_Mach();
1539           // !!!!! Stubs only need an oopmap right now, so bail out
1540           if (!mach->is_MachCall() && mach->as_MachSafePoint()->jvms()->method() == NULL) {
1541             // Write the oopmap directly to the code blob??!!
1542 #           ifdef ENABLE_ZAP_DEAD_LOCALS
1543             assert( !is_node_getting_a_safepoint(mach),  "logic does not match; false positive");
1544 #           endif
1545             delay_slot = NULL;
1546             continue;
1547           }
1548 
1549           int adjusted_offset = current_offset - Pipeline::instr_unit_size();
1550           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1551                                            adjusted_offset);
1552           // Generate an OopMap entry
1553           Process_OopMap_Node(mach, adjusted_offset);
1554         }
1555 
1556         // Insert the delay slot instruction
1557         delay_slot->emit(*cb, _regalloc);
1558 
1559         // Don't reuse it
1560         delay_slot = NULL;
1561       }
1562 
1563     } // End for all instructions in block
1564 
1565     // If the next block is the top of a loop, pad this block out to align
1566     // the loop top a little. Helps prevent pipe stalls at loop back branches.
1567     if (i < nblocks-1) {
1568       Block *nb = _cfg->get_block(i + 1);
1569       int padding = nb->alignment_padding(current_offset);
1570       if( padding > 0 ) {
1571         MachNode *nop = new (this) MachNopNode(padding / nop_size);
1572         block->insert_node(nop, block->number_of_nodes());
1573         _cfg->map_node_to_block(nop, block);
1574         nop->emit(*cb, _regalloc);
1575         current_offset = cb->insts_size();
1576       }
1577     }
1578     // Verify that the distance for generated before forward
1579     // short branches is still valid.
1580     guarantee((int)(blk_starts[i+1] - blk_starts[i]) >= (current_offset - blk_offset), "shouldn't increase block size");
1581 
1582     // Save new block start offset
1583     blk_starts[i] = blk_offset;
1584   } // End of for all blocks
1585   blk_starts[nblocks] = current_offset;
1586 
1587   non_safepoints.flush_at_end();
1588 
1589   // Offset too large?
1590   if (failing())  return;
1591 
1592   // Define a pseudo-label at the end of the code
1593   MacroAssembler(cb).bind( blk_labels[nblocks] );
1594 
1595   // Compute the size of the first block
1596   _first_block_size = blk_labels[1].loc_pos() - blk_labels[0].loc_pos();
1597 
1598   assert(cb->insts_size() < 500000, "method is unreasonably large");
1599 
1600 #ifdef ASSERT
1601   for (uint i = 0; i < nblocks; i++) { // For all blocks
1602     if (jmp_target[i] != 0) {
1603       int br_size = jmp_size[i];
1604       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
1605       if (!_matcher->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
1606         tty->print_cr("target (%d) - jmp_offset(%d) = offset (%d), jump_size(%d), jmp_block B%d, target_block B%d", blk_starts[jmp_target[i]], blk_starts[i] + jmp_offset[i], offset, br_size, i, jmp_target[i]);
1607         assert(false, "Displacement too large for short jmp");
1608       }
1609     }
1610   }
1611 #endif
1612 
1613 #ifndef PRODUCT
1614   // Information on the size of the method, without the extraneous code
1615   Scheduling::increment_method_size(cb->insts_size());
1616 #endif
1617 
1618   // ------------------
1619   // Fill in exception table entries.
1620   FillExceptionTables(inct_cnt, call_returns, inct_starts, blk_labels);
1621 
1622   // Only java methods have exception handlers and deopt handlers
1623   // class HandlerImpl is platform-specific and defined in the *.ad files.
1624   if (_method) {
1625     // Emit the exception handler code.
1626     _code_offsets.set_value(CodeOffsets::Exceptions, HandlerImpl::emit_exception_handler(*cb));
1627     // Emit the deopt handler code.
1628     _code_offsets.set_value(CodeOffsets::Deopt, HandlerImpl::emit_deopt_handler(*cb));
1629 
1630     // Emit the MethodHandle deopt handler code (if required).
1631     if (has_method_handle_invokes()) {
1632       // We can use the same code as for the normal deopt handler, we
1633       // just need a different entry point address.
1634       _code_offsets.set_value(CodeOffsets::DeoptMH, HandlerImpl::emit_deopt_handler(*cb));
1635     }
1636   }
1637 
1638   // One last check for failed CodeBuffer::expand:
1639   if ((cb->blob() == NULL) || (!CompileBroker::should_compile_new_jobs())) {
1640     C->record_failure("CodeCache is full");
1641     return;
1642   }
1643 
1644 #ifndef PRODUCT
1645   // Dump the assembly code, including basic-block numbers
1646   if (print_assembly()) {
1647     ttyLocker ttyl;  // keep the following output all in one block
1648     if (!VMThread::should_terminate()) {  // test this under the tty lock
1649       // This output goes directly to the tty, not the compiler log.
1650       // To enable tools to match it up with the compilation activity,
1651       // be sure to tag this tty output with the compile ID.
1652       if (xtty != NULL) {
1653         xtty->head("opto_assembly compile_id='%d'%s", compile_id(),
1654                    is_osr_compilation()    ? " compile_kind='osr'" :
1655                    "");
1656       }
1657       if (method() != NULL) {
1658         method()->print_metadata();
1659       }
1660       dump_asm(node_offsets, node_offset_limit);
1661       if (xtty != NULL) {
1662         xtty->tail("opto_assembly");
1663       }
1664     }
1665   }
1666 #endif
1667 
1668 }
1669 
1670 void Compile::FillExceptionTables(uint cnt, uint *call_returns, uint *inct_starts, Label *blk_labels) {
1671   _inc_table.set_size(cnt);
1672 
1673   uint inct_cnt = 0;
1674   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
1675     Block* block = _cfg->get_block(i);
1676     Node *n = NULL;
1677     int j;
1678 
1679     // Find the branch; ignore trailing NOPs.
1680     for (j = block->number_of_nodes() - 1; j >= 0; j--) {
1681       n = block->get_node(j);
1682       if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con) {
1683         break;
1684       }
1685     }
1686 
1687     // If we didn't find anything, continue
1688     if (j < 0) {
1689       continue;
1690     }
1691 
1692     // Compute ExceptionHandlerTable subtable entry and add it
1693     // (skip empty blocks)
1694     if (n->is_Catch()) {
1695 
1696       // Get the offset of the return from the call
1697       uint call_return = call_returns[block->_pre_order];
1698 #ifdef ASSERT
1699       assert( call_return > 0, "no call seen for this basic block" );
1700       while (block->get_node(--j)->is_MachProj()) ;
1701       assert(block->get_node(j)->is_MachCall(), "CatchProj must follow call");
1702 #endif
1703       // last instruction is a CatchNode, find it's CatchProjNodes
1704       int nof_succs = block->_num_succs;
1705       // allocate space
1706       GrowableArray<intptr_t> handler_bcis(nof_succs);
1707       GrowableArray<intptr_t> handler_pcos(nof_succs);
1708       // iterate through all successors
1709       for (int j = 0; j < nof_succs; j++) {
1710         Block* s = block->_succs[j];
1711         bool found_p = false;
1712         for (uint k = 1; k < s->num_preds(); k++) {
1713           Node* pk = s->pred(k);
1714           if (pk->is_CatchProj() && pk->in(0) == n) {
1715             const CatchProjNode* p = pk->as_CatchProj();
1716             found_p = true;
1717             // add the corresponding handler bci & pco information
1718             if (p->_con != CatchProjNode::fall_through_index) {
1719               // p leads to an exception handler (and is not fall through)
1720               assert(s == _cfg->get_block(s->_pre_order), "bad numbering");
1721               // no duplicates, please
1722               if (!handler_bcis.contains(p->handler_bci())) {
1723                 uint block_num = s->non_connector()->_pre_order;
1724                 handler_bcis.append(p->handler_bci());
1725                 handler_pcos.append(blk_labels[block_num].loc_pos());
1726               }
1727             }
1728           }
1729         }
1730         assert(found_p, "no matching predecessor found");
1731         // Note:  Due to empty block removal, one block may have
1732         // several CatchProj inputs, from the same Catch.
1733       }
1734 
1735       // Set the offset of the return from the call
1736       _handler_table.add_subtable(call_return, &handler_bcis, NULL, &handler_pcos);
1737       continue;
1738     }
1739 
1740     // Handle implicit null exception table updates
1741     if (n->is_MachNullCheck()) {
1742       uint block_num = block->non_connector_successor(0)->_pre_order;
1743       _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
1744       continue;
1745     }
1746     // Handle implicit exception table updates: trap instructions.
1747     if (n->is_Mach() && n->as_Mach()->is_TrapBasedCheckNode()) {
1748       uint block_num = block->non_connector_successor(0)->_pre_order;
1749       _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
1750       continue;
1751     }
1752   } // End of for all blocks fill in exception table entries
1753 }
1754 
1755 // Static Variables
1756 #ifndef PRODUCT
1757 uint Scheduling::_total_nop_size = 0;
1758 uint Scheduling::_total_method_size = 0;
1759 uint Scheduling::_total_branches = 0;
1760 uint Scheduling::_total_unconditional_delays = 0;
1761 uint Scheduling::_total_instructions_per_bundle[Pipeline::_max_instrs_per_cycle+1];
1762 #endif
1763 
1764 // Initializer for class Scheduling
1765 
1766 Scheduling::Scheduling(Arena *arena, Compile &compile)
1767   : _arena(arena),
1768     _cfg(compile.cfg()),
1769     _regalloc(compile.regalloc()),
1770     _reg_node(arena),
1771     _bundle_instr_count(0),
1772     _bundle_cycle_number(0),
1773     _scheduled(arena),
1774     _available(arena),
1775     _next_node(NULL),
1776     _bundle_use(0, 0, resource_count, &_bundle_use_elements[0]),
1777     _pinch_free_list(arena)
1778 #ifndef PRODUCT
1779   , _branches(0)
1780   , _unconditional_delays(0)
1781 #endif
1782 {
1783   // Create a MachNopNode
1784   _nop = new (&compile) MachNopNode();
1785 
1786   // Now that the nops are in the array, save the count
1787   // (but allow entries for the nops)
1788   _node_bundling_limit = compile.unique();
1789   uint node_max = _regalloc->node_regs_max_index();
1790 
1791   compile.set_node_bundling_limit(_node_bundling_limit);
1792 
1793   // This one is persistent within the Compile class
1794   _node_bundling_base = NEW_ARENA_ARRAY(compile.comp_arena(), Bundle, node_max);
1795 
1796   // Allocate space for fixed-size arrays
1797   _node_latency    = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
1798   _uses            = NEW_ARENA_ARRAY(arena, short,          node_max);
1799   _current_latency = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
1800 
1801   // Clear the arrays
1802   memset(_node_bundling_base, 0, node_max * sizeof(Bundle));
1803   memset(_node_latency,       0, node_max * sizeof(unsigned short));
1804   memset(_uses,               0, node_max * sizeof(short));
1805   memset(_current_latency,    0, node_max * sizeof(unsigned short));
1806 
1807   // Clear the bundling information
1808   memcpy(_bundle_use_elements, Pipeline_Use::elaborated_elements, sizeof(Pipeline_Use::elaborated_elements));
1809 
1810   // Get the last node
1811   Block* block = _cfg->get_block(_cfg->number_of_blocks() - 1);
1812 
1813   _next_node = block->get_node(block->number_of_nodes() - 1);
1814 }
1815 
1816 #ifndef PRODUCT
1817 // Scheduling destructor
1818 Scheduling::~Scheduling() {
1819   _total_branches             += _branches;
1820   _total_unconditional_delays += _unconditional_delays;
1821 }
1822 #endif
1823 
1824 // Step ahead "i" cycles
1825 void Scheduling::step(uint i) {
1826 
1827   Bundle *bundle = node_bundling(_next_node);
1828   bundle->set_starts_bundle();
1829 
1830   // Update the bundle record, but leave the flags information alone
1831   if (_bundle_instr_count > 0) {
1832     bundle->set_instr_count(_bundle_instr_count);
1833     bundle->set_resources_used(_bundle_use.resourcesUsed());
1834   }
1835 
1836   // Update the state information
1837   _bundle_instr_count = 0;
1838   _bundle_cycle_number += i;
1839   _bundle_use.step(i);
1840 }
1841 
1842 void Scheduling::step_and_clear() {
1843   Bundle *bundle = node_bundling(_next_node);
1844   bundle->set_starts_bundle();
1845 
1846   // Update the bundle record
1847   if (_bundle_instr_count > 0) {
1848     bundle->set_instr_count(_bundle_instr_count);
1849     bundle->set_resources_used(_bundle_use.resourcesUsed());
1850 
1851     _bundle_cycle_number += 1;
1852   }
1853 
1854   // Clear the bundling information
1855   _bundle_instr_count = 0;
1856   _bundle_use.reset();
1857 
1858   memcpy(_bundle_use_elements,
1859     Pipeline_Use::elaborated_elements,
1860     sizeof(Pipeline_Use::elaborated_elements));
1861 }
1862 
1863 // Perform instruction scheduling and bundling over the sequence of
1864 // instructions in backwards order.
1865 void Compile::ScheduleAndBundle() {
1866 
1867   // Don't optimize this if it isn't a method
1868   if (!_method)
1869     return;
1870 
1871   // Don't optimize this if scheduling is disabled
1872   if (!do_scheduling())
1873     return;
1874 
1875   // Scheduling code works only with pairs (8 bytes) maximum.
1876   if (max_vector_size() > 8)
1877     return;
1878 
1879   NOT_PRODUCT( TracePhase t2("isched", &_t_instrSched, TimeCompiler); )
1880 
1881   // Create a data structure for all the scheduling information
1882   Scheduling scheduling(Thread::current()->resource_area(), *this);
1883 
1884   // Walk backwards over each basic block, computing the needed alignment
1885   // Walk over all the basic blocks
1886   scheduling.DoScheduling();
1887 }
1888 
1889 // Compute the latency of all the instructions.  This is fairly simple,
1890 // because we already have a legal ordering.  Walk over the instructions
1891 // from first to last, and compute the latency of the instruction based
1892 // on the latency of the preceding instruction(s).
1893 void Scheduling::ComputeLocalLatenciesForward(const Block *bb) {
1894 #ifndef PRODUCT
1895   if (_cfg->C->trace_opto_output())
1896     tty->print("# -> ComputeLocalLatenciesForward\n");
1897 #endif
1898 
1899   // Walk over all the schedulable instructions
1900   for( uint j=_bb_start; j < _bb_end; j++ ) {
1901 
1902     // This is a kludge, forcing all latency calculations to start at 1.
1903     // Used to allow latency 0 to force an instruction to the beginning
1904     // of the bb
1905     uint latency = 1;
1906     Node *use = bb->get_node(j);
1907     uint nlen = use->len();
1908 
1909     // Walk over all the inputs
1910     for ( uint k=0; k < nlen; k++ ) {
1911       Node *def = use->in(k);
1912       if (!def)
1913         continue;
1914 
1915       uint l = _node_latency[def->_idx] + use->latency(k);
1916       if (latency < l)
1917         latency = l;
1918     }
1919 
1920     _node_latency[use->_idx] = latency;
1921 
1922 #ifndef PRODUCT
1923     if (_cfg->C->trace_opto_output()) {
1924       tty->print("# latency %4d: ", latency);
1925       use->dump();
1926     }
1927 #endif
1928   }
1929 
1930 #ifndef PRODUCT
1931   if (_cfg->C->trace_opto_output())
1932     tty->print("# <- ComputeLocalLatenciesForward\n");
1933 #endif
1934 
1935 } // end ComputeLocalLatenciesForward
1936 
1937 // See if this node fits into the present instruction bundle
1938 bool Scheduling::NodeFitsInBundle(Node *n) {
1939   uint n_idx = n->_idx;
1940 
1941   // If this is the unconditional delay instruction, then it fits
1942   if (n == _unconditional_delay_slot) {
1943 #ifndef PRODUCT
1944     if (_cfg->C->trace_opto_output())
1945       tty->print("#     NodeFitsInBundle [%4d]: TRUE; is in unconditional delay slot\n", n->_idx);
1946 #endif
1947     return (true);
1948   }
1949 
1950   // If the node cannot be scheduled this cycle, skip it
1951   if (_current_latency[n_idx] > _bundle_cycle_number) {
1952 #ifndef PRODUCT
1953     if (_cfg->C->trace_opto_output())
1954       tty->print("#     NodeFitsInBundle [%4d]: FALSE; latency %4d > %d\n",
1955         n->_idx, _current_latency[n_idx], _bundle_cycle_number);
1956 #endif
1957     return (false);
1958   }
1959 
1960   const Pipeline *node_pipeline = n->pipeline();
1961 
1962   uint instruction_count = node_pipeline->instructionCount();
1963   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
1964     instruction_count = 0;
1965   else if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
1966     instruction_count++;
1967 
1968   if (_bundle_instr_count + instruction_count > Pipeline::_max_instrs_per_cycle) {
1969 #ifndef PRODUCT
1970     if (_cfg->C->trace_opto_output())
1971       tty->print("#     NodeFitsInBundle [%4d]: FALSE; too many instructions: %d > %d\n",
1972         n->_idx, _bundle_instr_count + instruction_count, Pipeline::_max_instrs_per_cycle);
1973 #endif
1974     return (false);
1975   }
1976 
1977   // Don't allow non-machine nodes to be handled this way
1978   if (!n->is_Mach() && instruction_count == 0)
1979     return (false);
1980 
1981   // See if there is any overlap
1982   uint delay = _bundle_use.full_latency(0, node_pipeline->resourceUse());
1983 
1984   if (delay > 0) {
1985 #ifndef PRODUCT
1986     if (_cfg->C->trace_opto_output())
1987       tty->print("#     NodeFitsInBundle [%4d]: FALSE; functional units overlap\n", n_idx);
1988 #endif
1989     return false;
1990   }
1991 
1992 #ifndef PRODUCT
1993   if (_cfg->C->trace_opto_output())
1994     tty->print("#     NodeFitsInBundle [%4d]:  TRUE\n", n_idx);
1995 #endif
1996 
1997   return true;
1998 }
1999 
2000 Node * Scheduling::ChooseNodeToBundle() {
2001   uint siz = _available.size();
2002 
2003   if (siz == 0) {
2004 
2005 #ifndef PRODUCT
2006     if (_cfg->C->trace_opto_output())
2007       tty->print("#   ChooseNodeToBundle: NULL\n");
2008 #endif
2009     return (NULL);
2010   }
2011 
2012   // Fast path, if only 1 instruction in the bundle
2013   if (siz == 1) {
2014 #ifndef PRODUCT
2015     if (_cfg->C->trace_opto_output()) {
2016       tty->print("#   ChooseNodeToBundle (only 1): ");
2017       _available[0]->dump();
2018     }
2019 #endif
2020     return (_available[0]);
2021   }
2022 
2023   // Don't bother, if the bundle is already full
2024   if (_bundle_instr_count < Pipeline::_max_instrs_per_cycle) {
2025     for ( uint i = 0; i < siz; i++ ) {
2026       Node *n = _available[i];
2027 
2028       // Skip projections, we'll handle them another way
2029       if (n->is_Proj())
2030         continue;
2031 
2032       // This presupposed that instructions are inserted into the
2033       // available list in a legality order; i.e. instructions that
2034       // must be inserted first are at the head of the list
2035       if (NodeFitsInBundle(n)) {
2036 #ifndef PRODUCT
2037         if (_cfg->C->trace_opto_output()) {
2038           tty->print("#   ChooseNodeToBundle: ");
2039           n->dump();
2040         }
2041 #endif
2042         return (n);
2043       }
2044     }
2045   }
2046 
2047   // Nothing fits in this bundle, choose the highest priority
2048 #ifndef PRODUCT
2049   if (_cfg->C->trace_opto_output()) {
2050     tty->print("#   ChooseNodeToBundle: ");
2051     _available[0]->dump();
2052   }
2053 #endif
2054 
2055   return _available[0];
2056 }
2057 
2058 void Scheduling::AddNodeToAvailableList(Node *n) {
2059   assert( !n->is_Proj(), "projections never directly made available" );
2060 #ifndef PRODUCT
2061   if (_cfg->C->trace_opto_output()) {
2062     tty->print("#   AddNodeToAvailableList: ");
2063     n->dump();
2064   }
2065 #endif
2066 
2067   int latency = _current_latency[n->_idx];
2068 
2069   // Insert in latency order (insertion sort)
2070   uint i;
2071   for ( i=0; i < _available.size(); i++ )
2072     if (_current_latency[_available[i]->_idx] > latency)
2073       break;
2074 
2075   // Special Check for compares following branches
2076   if( n->is_Mach() && _scheduled.size() > 0 ) {
2077     int op = n->as_Mach()->ideal_Opcode();
2078     Node *last = _scheduled[0];
2079     if( last->is_MachIf() && last->in(1) == n &&
2080         ( op == Op_CmpI ||
2081           op == Op_CmpU ||
2082           op == Op_CmpP ||
2083           op == Op_CmpF ||
2084           op == Op_CmpD ||
2085           op == Op_CmpL ) ) {
2086 
2087       // Recalculate position, moving to front of same latency
2088       for ( i=0 ; i < _available.size(); i++ )
2089         if (_current_latency[_available[i]->_idx] >= latency)
2090           break;
2091     }
2092   }
2093 
2094   // Insert the node in the available list
2095   _available.insert(i, n);
2096 
2097 #ifndef PRODUCT
2098   if (_cfg->C->trace_opto_output())
2099     dump_available();
2100 #endif
2101 }
2102 
2103 void Scheduling::DecrementUseCounts(Node *n, const Block *bb) {
2104   for ( uint i=0; i < n->len(); i++ ) {
2105     Node *def = n->in(i);
2106     if (!def) continue;
2107     if( def->is_Proj() )        // If this is a machine projection, then
2108       def = def->in(0);         // propagate usage thru to the base instruction
2109 
2110     if(_cfg->get_block_for_node(def) != bb) { // Ignore if not block-local
2111       continue;
2112     }
2113 
2114     // Compute the latency
2115     uint l = _bundle_cycle_number + n->latency(i);
2116     if (_current_latency[def->_idx] < l)
2117       _current_latency[def->_idx] = l;
2118 
2119     // If this does not have uses then schedule it
2120     if ((--_uses[def->_idx]) == 0)
2121       AddNodeToAvailableList(def);
2122   }
2123 }
2124 
2125 void Scheduling::AddNodeToBundle(Node *n, const Block *bb) {
2126 #ifndef PRODUCT
2127   if (_cfg->C->trace_opto_output()) {
2128     tty->print("#   AddNodeToBundle: ");
2129     n->dump();
2130   }
2131 #endif
2132 
2133   // Remove this from the available list
2134   uint i;
2135   for (i = 0; i < _available.size(); i++)
2136     if (_available[i] == n)
2137       break;
2138   assert(i < _available.size(), "entry in _available list not found");
2139   _available.remove(i);
2140 
2141   // See if this fits in the current bundle
2142   const Pipeline *node_pipeline = n->pipeline();
2143   const Pipeline_Use& node_usage = node_pipeline->resourceUse();
2144 
2145   // Check for instructions to be placed in the delay slot. We
2146   // do this before we actually schedule the current instruction,
2147   // because the delay slot follows the current instruction.
2148   if (Pipeline::_branch_has_delay_slot &&
2149       node_pipeline->hasBranchDelay() &&
2150       !_unconditional_delay_slot) {
2151 
2152     uint siz = _available.size();
2153 
2154     // Conditional branches can support an instruction that
2155     // is unconditionally executed and not dependent by the
2156     // branch, OR a conditionally executed instruction if
2157     // the branch is taken.  In practice, this means that
2158     // the first instruction at the branch target is
2159     // copied to the delay slot, and the branch goes to
2160     // the instruction after that at the branch target
2161     if ( n->is_MachBranch() ) {
2162 
2163       assert( !n->is_MachNullCheck(), "should not look for delay slot for Null Check" );
2164       assert( !n->is_Catch(),         "should not look for delay slot for Catch" );
2165 
2166 #ifndef PRODUCT
2167       _branches++;
2168 #endif
2169 
2170       // At least 1 instruction is on the available list
2171       // that is not dependent on the branch
2172       for (uint i = 0; i < siz; i++) {
2173         Node *d = _available[i];
2174         const Pipeline *avail_pipeline = d->pipeline();
2175 
2176         // Don't allow safepoints in the branch shadow, that will
2177         // cause a number of difficulties
2178         if ( avail_pipeline->instructionCount() == 1 &&
2179             !avail_pipeline->hasMultipleBundles() &&
2180             !avail_pipeline->hasBranchDelay() &&
2181             Pipeline::instr_has_unit_size() &&
2182             d->size(_regalloc) == Pipeline::instr_unit_size() &&
2183             NodeFitsInBundle(d) &&
2184             !node_bundling(d)->used_in_delay()) {
2185 
2186           if (d->is_Mach() && !d->is_MachSafePoint()) {
2187             // A node that fits in the delay slot was found, so we need to
2188             // set the appropriate bits in the bundle pipeline information so
2189             // that it correctly indicates resource usage.  Later, when we
2190             // attempt to add this instruction to the bundle, we will skip
2191             // setting the resource usage.
2192             _unconditional_delay_slot = d;
2193             node_bundling(n)->set_use_unconditional_delay();
2194             node_bundling(d)->set_used_in_unconditional_delay();
2195             _bundle_use.add_usage(avail_pipeline->resourceUse());
2196             _current_latency[d->_idx] = _bundle_cycle_number;
2197             _next_node = d;
2198             ++_bundle_instr_count;
2199 #ifndef PRODUCT
2200             _unconditional_delays++;
2201 #endif
2202             break;
2203           }
2204         }
2205       }
2206     }
2207 
2208     // No delay slot, add a nop to the usage
2209     if (!_unconditional_delay_slot) {
2210       // See if adding an instruction in the delay slot will overflow
2211       // the bundle.
2212       if (!NodeFitsInBundle(_nop)) {
2213 #ifndef PRODUCT
2214         if (_cfg->C->trace_opto_output())
2215           tty->print("#  *** STEP(1 instruction for delay slot) ***\n");
2216 #endif
2217         step(1);
2218       }
2219 
2220       _bundle_use.add_usage(_nop->pipeline()->resourceUse());
2221       _next_node = _nop;
2222       ++_bundle_instr_count;
2223     }
2224 
2225     // See if the instruction in the delay slot requires a
2226     // step of the bundles
2227     if (!NodeFitsInBundle(n)) {
2228 #ifndef PRODUCT
2229         if (_cfg->C->trace_opto_output())
2230           tty->print("#  *** STEP(branch won't fit) ***\n");
2231 #endif
2232         // Update the state information
2233         _bundle_instr_count = 0;
2234         _bundle_cycle_number += 1;
2235         _bundle_use.step(1);
2236     }
2237   }
2238 
2239   // Get the number of instructions
2240   uint instruction_count = node_pipeline->instructionCount();
2241   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
2242     instruction_count = 0;
2243 
2244   // Compute the latency information
2245   uint delay = 0;
2246 
2247   if (instruction_count > 0 || !node_pipeline->mayHaveNoCode()) {
2248     int relative_latency = _current_latency[n->_idx] - _bundle_cycle_number;
2249     if (relative_latency < 0)
2250       relative_latency = 0;
2251 
2252     delay = _bundle_use.full_latency(relative_latency, node_usage);
2253 
2254     // Does not fit in this bundle, start a new one
2255     if (delay > 0) {
2256       step(delay);
2257 
2258 #ifndef PRODUCT
2259       if (_cfg->C->trace_opto_output())
2260         tty->print("#  *** STEP(%d) ***\n", delay);
2261 #endif
2262     }
2263   }
2264 
2265   // If this was placed in the delay slot, ignore it
2266   if (n != _unconditional_delay_slot) {
2267 
2268     if (delay == 0) {
2269       if (node_pipeline->hasMultipleBundles()) {
2270 #ifndef PRODUCT
2271         if (_cfg->C->trace_opto_output())
2272           tty->print("#  *** STEP(multiple instructions) ***\n");
2273 #endif
2274         step(1);
2275       }
2276 
2277       else if (instruction_count + _bundle_instr_count > Pipeline::_max_instrs_per_cycle) {
2278 #ifndef PRODUCT
2279         if (_cfg->C->trace_opto_output())
2280           tty->print("#  *** STEP(%d >= %d instructions) ***\n",
2281             instruction_count + _bundle_instr_count,
2282             Pipeline::_max_instrs_per_cycle);
2283 #endif
2284         step(1);
2285       }
2286     }
2287 
2288     if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
2289       _bundle_instr_count++;
2290 
2291     // Set the node's latency
2292     _current_latency[n->_idx] = _bundle_cycle_number;
2293 
2294     // Now merge the functional unit information
2295     if (instruction_count > 0 || !node_pipeline->mayHaveNoCode())
2296       _bundle_use.add_usage(node_usage);
2297 
2298     // Increment the number of instructions in this bundle
2299     _bundle_instr_count += instruction_count;
2300 
2301     // Remember this node for later
2302     if (n->is_Mach())
2303       _next_node = n;
2304   }
2305 
2306   // It's possible to have a BoxLock in the graph and in the _bbs mapping but
2307   // not in the bb->_nodes array.  This happens for debug-info-only BoxLocks.
2308   // 'Schedule' them (basically ignore in the schedule) but do not insert them
2309   // into the block.  All other scheduled nodes get put in the schedule here.
2310   int op = n->Opcode();
2311   if( (op == Op_Node && n->req() == 0) || // anti-dependence node OR
2312       (op != Op_Node &&         // Not an unused antidepedence node and
2313        // not an unallocated boxlock
2314        (OptoReg::is_valid(_regalloc->get_reg_first(n)) || op != Op_BoxLock)) ) {
2315 
2316     // Push any trailing projections
2317     if( bb->get_node(bb->number_of_nodes()-1) != n ) {
2318       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2319         Node *foi = n->fast_out(i);
2320         if( foi->is_Proj() )
2321           _scheduled.push(foi);
2322       }
2323     }
2324 
2325     // Put the instruction in the schedule list
2326     _scheduled.push(n);
2327   }
2328 
2329 #ifndef PRODUCT
2330   if (_cfg->C->trace_opto_output())
2331     dump_available();
2332 #endif
2333 
2334   // Walk all the definitions, decrementing use counts, and
2335   // if a definition has a 0 use count, place it in the available list.
2336   DecrementUseCounts(n,bb);
2337 }
2338 
2339 // This method sets the use count within a basic block.  We will ignore all
2340 // uses outside the current basic block.  As we are doing a backwards walk,
2341 // any node we reach that has a use count of 0 may be scheduled.  This also
2342 // avoids the problem of cyclic references from phi nodes, as long as phi
2343 // nodes are at the front of the basic block.  This method also initializes
2344 // the available list to the set of instructions that have no uses within this
2345 // basic block.
2346 void Scheduling::ComputeUseCount(const Block *bb) {
2347 #ifndef PRODUCT
2348   if (_cfg->C->trace_opto_output())
2349     tty->print("# -> ComputeUseCount\n");
2350 #endif
2351 
2352   // Clear the list of available and scheduled instructions, just in case
2353   _available.clear();
2354   _scheduled.clear();
2355 
2356   // No delay slot specified
2357   _unconditional_delay_slot = NULL;
2358 
2359 #ifdef ASSERT
2360   for( uint i=0; i < bb->number_of_nodes(); i++ )
2361     assert( _uses[bb->get_node(i)->_idx] == 0, "_use array not clean" );
2362 #endif
2363 
2364   // Force the _uses count to never go to zero for unscheduable pieces
2365   // of the block
2366   for( uint k = 0; k < _bb_start; k++ )
2367     _uses[bb->get_node(k)->_idx] = 1;
2368   for( uint l = _bb_end; l < bb->number_of_nodes(); l++ )
2369     _uses[bb->get_node(l)->_idx] = 1;
2370 
2371   // Iterate backwards over the instructions in the block.  Don't count the
2372   // branch projections at end or the block header instructions.
2373   for( uint j = _bb_end-1; j >= _bb_start; j-- ) {
2374     Node *n = bb->get_node(j);
2375     if( n->is_Proj() ) continue; // Projections handled another way
2376 
2377     // Account for all uses
2378     for ( uint k = 0; k < n->len(); k++ ) {
2379       Node *inp = n->in(k);
2380       if (!inp) continue;
2381       assert(inp != n, "no cycles allowed" );
2382       if (_cfg->get_block_for_node(inp) == bb) { // Block-local use?
2383         if (inp->is_Proj()) { // Skip through Proj's
2384           inp = inp->in(0);
2385         }
2386         ++_uses[inp->_idx];     // Count 1 block-local use
2387       }
2388     }
2389 
2390     // If this instruction has a 0 use count, then it is available
2391     if (!_uses[n->_idx]) {
2392       _current_latency[n->_idx] = _bundle_cycle_number;
2393       AddNodeToAvailableList(n);
2394     }
2395 
2396 #ifndef PRODUCT
2397     if (_cfg->C->trace_opto_output()) {
2398       tty->print("#   uses: %3d: ", _uses[n->_idx]);
2399       n->dump();
2400     }
2401 #endif
2402   }
2403 
2404 #ifndef PRODUCT
2405   if (_cfg->C->trace_opto_output())
2406     tty->print("# <- ComputeUseCount\n");
2407 #endif
2408 }
2409 
2410 // This routine performs scheduling on each basic block in reverse order,
2411 // using instruction latencies and taking into account function unit
2412 // availability.
2413 void Scheduling::DoScheduling() {
2414 #ifndef PRODUCT
2415   if (_cfg->C->trace_opto_output())
2416     tty->print("# -> DoScheduling\n");
2417 #endif
2418 
2419   Block *succ_bb = NULL;
2420   Block *bb;
2421 
2422   // Walk over all the basic blocks in reverse order
2423   for (int i = _cfg->number_of_blocks() - 1; i >= 0; succ_bb = bb, i--) {
2424     bb = _cfg->get_block(i);
2425 
2426 #ifndef PRODUCT
2427     if (_cfg->C->trace_opto_output()) {
2428       tty->print("#  Schedule BB#%03d (initial)\n", i);
2429       for (uint j = 0; j < bb->number_of_nodes(); j++) {
2430         bb->get_node(j)->dump();
2431       }
2432     }
2433 #endif
2434 
2435     // On the head node, skip processing
2436     if (bb == _cfg->get_root_block()) {
2437       continue;
2438     }
2439 
2440     // Skip empty, connector blocks
2441     if (bb->is_connector())
2442       continue;
2443 
2444     // If the following block is not the sole successor of
2445     // this one, then reset the pipeline information
2446     if (bb->_num_succs != 1 || bb->non_connector_successor(0) != succ_bb) {
2447 #ifndef PRODUCT
2448       if (_cfg->C->trace_opto_output()) {
2449         tty->print("*** bundle start of next BB, node %d, for %d instructions\n",
2450                    _next_node->_idx, _bundle_instr_count);
2451       }
2452 #endif
2453       step_and_clear();
2454     }
2455 
2456     // Leave untouched the starting instruction, any Phis, a CreateEx node
2457     // or Top.  bb->get_node(_bb_start) is the first schedulable instruction.
2458     _bb_end = bb->number_of_nodes()-1;
2459     for( _bb_start=1; _bb_start <= _bb_end; _bb_start++ ) {
2460       Node *n = bb->get_node(_bb_start);
2461       // Things not matched, like Phinodes and ProjNodes don't get scheduled.
2462       // Also, MachIdealNodes do not get scheduled
2463       if( !n->is_Mach() ) continue;     // Skip non-machine nodes
2464       MachNode *mach = n->as_Mach();
2465       int iop = mach->ideal_Opcode();
2466       if( iop == Op_CreateEx ) continue; // CreateEx is pinned
2467       if( iop == Op_Con ) continue;      // Do not schedule Top
2468       if( iop == Op_Node &&     // Do not schedule PhiNodes, ProjNodes
2469           mach->pipeline() == MachNode::pipeline_class() &&
2470           !n->is_SpillCopy() )  // Breakpoints, Prolog, etc
2471         continue;
2472       break;                    // Funny loop structure to be sure...
2473     }
2474     // Compute last "interesting" instruction in block - last instruction we
2475     // might schedule.  _bb_end points just after last schedulable inst.  We
2476     // normally schedule conditional branches (despite them being forced last
2477     // in the block), because they have delay slots we can fill.  Calls all
2478     // have their delay slots filled in the template expansions, so we don't
2479     // bother scheduling them.
2480     Node *last = bb->get_node(_bb_end);
2481     // Ignore trailing NOPs.
2482     while (_bb_end > 0 && last->is_Mach() &&
2483            last->as_Mach()->ideal_Opcode() == Op_Con) {
2484       last = bb->get_node(--_bb_end);
2485     }
2486     assert(!last->is_Mach() || last->as_Mach()->ideal_Opcode() != Op_Con, "");
2487     if( last->is_Catch() ||
2488        // Exclude unreachable path case when Halt node is in a separate block.
2489        (_bb_end > 1 && last->is_Mach() && last->as_Mach()->ideal_Opcode() == Op_Halt) ) {
2490       // There must be a prior call.  Skip it.
2491       while( !bb->get_node(--_bb_end)->is_MachCall() ) {
2492         assert( bb->get_node(_bb_end)->is_MachProj(), "skipping projections after expected call" );
2493       }
2494     } else if( last->is_MachNullCheck() ) {
2495       // Backup so the last null-checked memory instruction is
2496       // outside the schedulable range. Skip over the nullcheck,
2497       // projection, and the memory nodes.
2498       Node *mem = last->in(1);
2499       do {
2500         _bb_end--;
2501       } while (mem != bb->get_node(_bb_end));
2502     } else {
2503       // Set _bb_end to point after last schedulable inst.
2504       _bb_end++;
2505     }
2506 
2507     assert( _bb_start <= _bb_end, "inverted block ends" );
2508 
2509     // Compute the register antidependencies for the basic block
2510     ComputeRegisterAntidependencies(bb);
2511     if (_cfg->C->failing())  return;  // too many D-U pinch points
2512 
2513     // Compute intra-bb latencies for the nodes
2514     ComputeLocalLatenciesForward(bb);
2515 
2516     // Compute the usage within the block, and set the list of all nodes
2517     // in the block that have no uses within the block.
2518     ComputeUseCount(bb);
2519 
2520     // Schedule the remaining instructions in the block
2521     while ( _available.size() > 0 ) {
2522       Node *n = ChooseNodeToBundle();
2523       guarantee(n != NULL, "no nodes available");
2524       AddNodeToBundle(n,bb);
2525     }
2526 
2527     assert( _scheduled.size() == _bb_end - _bb_start, "wrong number of instructions" );
2528 #ifdef ASSERT
2529     for( uint l = _bb_start; l < _bb_end; l++ ) {
2530       Node *n = bb->get_node(l);
2531       uint m;
2532       for( m = 0; m < _bb_end-_bb_start; m++ )
2533         if( _scheduled[m] == n )
2534           break;
2535       assert( m < _bb_end-_bb_start, "instruction missing in schedule" );
2536     }
2537 #endif
2538 
2539     // Now copy the instructions (in reverse order) back to the block
2540     for ( uint k = _bb_start; k < _bb_end; k++ )
2541       bb->map_node(_scheduled[_bb_end-k-1], k);
2542 
2543 #ifndef PRODUCT
2544     if (_cfg->C->trace_opto_output()) {
2545       tty->print("#  Schedule BB#%03d (final)\n", i);
2546       uint current = 0;
2547       for (uint j = 0; j < bb->number_of_nodes(); j++) {
2548         Node *n = bb->get_node(j);
2549         if( valid_bundle_info(n) ) {
2550           Bundle *bundle = node_bundling(n);
2551           if (bundle->instr_count() > 0 || bundle->flags() > 0) {
2552             tty->print("*** Bundle: ");
2553             bundle->dump();
2554           }
2555           n->dump();
2556         }
2557       }
2558     }
2559 #endif
2560 #ifdef ASSERT
2561   verify_good_schedule(bb,"after block local scheduling");
2562 #endif
2563   }
2564 
2565 #ifndef PRODUCT
2566   if (_cfg->C->trace_opto_output())
2567     tty->print("# <- DoScheduling\n");
2568 #endif
2569 
2570   // Record final node-bundling array location
2571   _regalloc->C->set_node_bundling_base(_node_bundling_base);
2572 
2573 } // end DoScheduling
2574 
2575 // Verify that no live-range used in the block is killed in the block by a
2576 // wrong DEF.  This doesn't verify live-ranges that span blocks.
2577 
2578 // Check for edge existence.  Used to avoid adding redundant precedence edges.
2579 static bool edge_from_to( Node *from, Node *to ) {
2580   for( uint i=0; i<from->len(); i++ )
2581     if( from->in(i) == to )
2582       return true;
2583   return false;
2584 }
2585 
2586 #ifdef ASSERT
2587 void Scheduling::verify_do_def( Node *n, OptoReg::Name def, const char *msg ) {
2588   // Check for bad kills
2589   if( OptoReg::is_valid(def) ) { // Ignore stores & control flow
2590     Node *prior_use = _reg_node[def];
2591     if( prior_use && !edge_from_to(prior_use,n) ) {
2592       tty->print("%s = ",OptoReg::as_VMReg(def)->name());
2593       n->dump();
2594       tty->print_cr("...");
2595       prior_use->dump();
2596       assert(edge_from_to(prior_use,n),msg);
2597     }
2598     _reg_node.map(def,NULL); // Kill live USEs
2599   }
2600 }
2601 
2602 void Scheduling::verify_good_schedule( Block *b, const char *msg ) {
2603 
2604   // Zap to something reasonable for the verify code
2605   _reg_node.clear();
2606 
2607   // Walk over the block backwards.  Check to make sure each DEF doesn't
2608   // kill a live value (other than the one it's supposed to).  Add each
2609   // USE to the live set.
2610   for( uint i = b->number_of_nodes()-1; i >= _bb_start; i-- ) {
2611     Node *n = b->get_node(i);
2612     int n_op = n->Opcode();
2613     if( n_op == Op_MachProj && n->ideal_reg() == MachProjNode::fat_proj ) {
2614       // Fat-proj kills a slew of registers
2615       RegMask rm = n->out_RegMask();// Make local copy
2616       while( rm.is_NotEmpty() ) {
2617         OptoReg::Name kill = rm.find_first_elem();
2618         rm.Remove(kill);
2619         verify_do_def( n, kill, msg );
2620       }
2621     } else if( n_op != Op_Node ) { // Avoid brand new antidependence nodes
2622       // Get DEF'd registers the normal way
2623       verify_do_def( n, _regalloc->get_reg_first(n), msg );
2624       verify_do_def( n, _regalloc->get_reg_second(n), msg );
2625     }
2626 
2627     // Now make all USEs live
2628     for( uint i=1; i<n->req(); i++ ) {
2629       Node *def = n->in(i);
2630       assert(def != 0, "input edge required");
2631       OptoReg::Name reg_lo = _regalloc->get_reg_first(def);
2632       OptoReg::Name reg_hi = _regalloc->get_reg_second(def);
2633       if( OptoReg::is_valid(reg_lo) ) {
2634         assert(!_reg_node[reg_lo] || edge_from_to(_reg_node[reg_lo],def), msg);
2635         _reg_node.map(reg_lo,n);
2636       }
2637       if( OptoReg::is_valid(reg_hi) ) {
2638         assert(!_reg_node[reg_hi] || edge_from_to(_reg_node[reg_hi],def), msg);
2639         _reg_node.map(reg_hi,n);
2640       }
2641     }
2642 
2643   }
2644 
2645   // Zap to something reasonable for the Antidependence code
2646   _reg_node.clear();
2647 }
2648 #endif
2649 
2650 // Conditionally add precedence edges.  Avoid putting edges on Projs.
2651 static void add_prec_edge_from_to( Node *from, Node *to ) {
2652   if( from->is_Proj() ) {       // Put precedence edge on Proj's input
2653     assert( from->req() == 1 && (from->len() == 1 || from->in(1)==0), "no precedence edges on projections" );
2654     from = from->in(0);
2655   }
2656   if( from != to &&             // No cycles (for things like LD L0,[L0+4] )
2657       !edge_from_to( from, to ) ) // Avoid duplicate edge
2658     from->add_prec(to);
2659 }
2660 
2661 void Scheduling::anti_do_def( Block *b, Node *def, OptoReg::Name def_reg, int is_def ) {
2662   if( !OptoReg::is_valid(def_reg) ) // Ignore stores & control flow
2663     return;
2664 
2665   Node *pinch = _reg_node[def_reg]; // Get pinch point
2666   if ((pinch == NULL) || _cfg->get_block_for_node(pinch) != b || // No pinch-point yet?
2667       is_def ) {    // Check for a true def (not a kill)
2668     _reg_node.map(def_reg,def); // Record def/kill as the optimistic pinch-point
2669     return;
2670   }
2671 
2672   Node *kill = def;             // Rename 'def' to more descriptive 'kill'
2673   debug_only( def = (Node*)0xdeadbeef; )
2674 
2675   // After some number of kills there _may_ be a later def
2676   Node *later_def = NULL;
2677 
2678   // Finding a kill requires a real pinch-point.
2679   // Check for not already having a pinch-point.
2680   // Pinch points are Op_Node's.
2681   if( pinch->Opcode() != Op_Node ) { // Or later-def/kill as pinch-point?
2682     later_def = pinch;            // Must be def/kill as optimistic pinch-point
2683     if ( _pinch_free_list.size() > 0) {
2684       pinch = _pinch_free_list.pop();
2685     } else {
2686       pinch = new (_cfg->C) Node(1); // Pinch point to-be
2687     }
2688     if (pinch->_idx >= _regalloc->node_regs_max_index()) {
2689       _cfg->C->record_method_not_compilable("too many D-U pinch points");
2690       return;
2691     }
2692     _cfg->map_node_to_block(pinch, b);      // Pretend it's valid in this block (lazy init)
2693     _reg_node.map(def_reg,pinch); // Record pinch-point
2694     //_regalloc->set_bad(pinch->_idx); // Already initialized this way.
2695     if( later_def->outcnt() == 0 || later_def->ideal_reg() == MachProjNode::fat_proj ) { // Distinguish def from kill
2696       pinch->init_req(0, _cfg->C->top());     // set not NULL for the next call
2697       add_prec_edge_from_to(later_def,pinch); // Add edge from kill to pinch
2698       later_def = NULL;           // and no later def
2699     }
2700     pinch->set_req(0,later_def);  // Hook later def so we can find it
2701   } else {                        // Else have valid pinch point
2702     if( pinch->in(0) )            // If there is a later-def
2703       later_def = pinch->in(0);   // Get it
2704   }
2705 
2706   // Add output-dependence edge from later def to kill
2707   if( later_def )               // If there is some original def
2708     add_prec_edge_from_to(later_def,kill); // Add edge from def to kill
2709 
2710   // See if current kill is also a use, and so is forced to be the pinch-point.
2711   if( pinch->Opcode() == Op_Node ) {
2712     Node *uses = kill->is_Proj() ? kill->in(0) : kill;
2713     for( uint i=1; i<uses->req(); i++ ) {
2714       if( _regalloc->get_reg_first(uses->in(i)) == def_reg ||
2715           _regalloc->get_reg_second(uses->in(i)) == def_reg ) {
2716         // Yes, found a use/kill pinch-point
2717         pinch->set_req(0,NULL);  //
2718         pinch->replace_by(kill); // Move anti-dep edges up
2719         pinch = kill;
2720         _reg_node.map(def_reg,pinch);
2721         return;
2722       }
2723     }
2724   }
2725 
2726   // Add edge from kill to pinch-point
2727   add_prec_edge_from_to(kill,pinch);
2728 }
2729 
2730 void Scheduling::anti_do_use( Block *b, Node *use, OptoReg::Name use_reg ) {
2731   if( !OptoReg::is_valid(use_reg) ) // Ignore stores & control flow
2732     return;
2733   Node *pinch = _reg_node[use_reg]; // Get pinch point
2734   // Check for no later def_reg/kill in block
2735   if ((pinch != NULL) && _cfg->get_block_for_node(pinch) == b &&
2736       // Use has to be block-local as well
2737       _cfg->get_block_for_node(use) == b) {
2738     if( pinch->Opcode() == Op_Node && // Real pinch-point (not optimistic?)
2739         pinch->req() == 1 ) {   // pinch not yet in block?
2740       pinch->del_req(0);        // yank pointer to later-def, also set flag
2741       // Insert the pinch-point in the block just after the last use
2742       b->insert_node(pinch, b->find_node(use) + 1);
2743       _bb_end++;                // Increase size scheduled region in block
2744     }
2745 
2746     add_prec_edge_from_to(pinch,use);
2747   }
2748 }
2749 
2750 // We insert antidependences between the reads and following write of
2751 // allocated registers to prevent illegal code motion. Hopefully, the
2752 // number of added references should be fairly small, especially as we
2753 // are only adding references within the current basic block.
2754 void Scheduling::ComputeRegisterAntidependencies(Block *b) {
2755 
2756 #ifdef ASSERT
2757   verify_good_schedule(b,"before block local scheduling");
2758 #endif
2759 
2760   // A valid schedule, for each register independently, is an endless cycle
2761   // of: a def, then some uses (connected to the def by true dependencies),
2762   // then some kills (defs with no uses), finally the cycle repeats with a new
2763   // def.  The uses are allowed to float relative to each other, as are the
2764   // kills.  No use is allowed to slide past a kill (or def).  This requires
2765   // antidependencies between all uses of a single def and all kills that
2766   // follow, up to the next def.  More edges are redundant, because later defs
2767   // & kills are already serialized with true or antidependencies.  To keep
2768   // the edge count down, we add a 'pinch point' node if there's more than
2769   // one use or more than one kill/def.
2770 
2771   // We add dependencies in one bottom-up pass.
2772 
2773   // For each instruction we handle it's DEFs/KILLs, then it's USEs.
2774 
2775   // For each DEF/KILL, we check to see if there's a prior DEF/KILL for this
2776   // register.  If not, we record the DEF/KILL in _reg_node, the
2777   // register-to-def mapping.  If there is a prior DEF/KILL, we insert a
2778   // "pinch point", a new Node that's in the graph but not in the block.
2779   // We put edges from the prior and current DEF/KILLs to the pinch point.
2780   // We put the pinch point in _reg_node.  If there's already a pinch point
2781   // we merely add an edge from the current DEF/KILL to the pinch point.
2782 
2783   // After doing the DEF/KILLs, we handle USEs.  For each used register, we
2784   // put an edge from the pinch point to the USE.
2785 
2786   // To be expedient, the _reg_node array is pre-allocated for the whole
2787   // compilation.  _reg_node is lazily initialized; it either contains a NULL,
2788   // or a valid def/kill/pinch-point, or a leftover node from some prior
2789   // block.  Leftover node from some prior block is treated like a NULL (no
2790   // prior def, so no anti-dependence needed).  Valid def is distinguished by
2791   // it being in the current block.
2792   bool fat_proj_seen = false;
2793   uint last_safept = _bb_end-1;
2794   Node* end_node         = (_bb_end-1 >= _bb_start) ? b->get_node(last_safept) : NULL;
2795   Node* last_safept_node = end_node;
2796   for( uint i = _bb_end-1; i >= _bb_start; i-- ) {
2797     Node *n = b->get_node(i);
2798     int is_def = n->outcnt();   // def if some uses prior to adding precedence edges
2799     if( n->is_MachProj() && n->ideal_reg() == MachProjNode::fat_proj ) {
2800       // Fat-proj kills a slew of registers
2801       // This can add edges to 'n' and obscure whether or not it was a def,
2802       // hence the is_def flag.
2803       fat_proj_seen = true;
2804       RegMask rm = n->out_RegMask();// Make local copy
2805       while( rm.is_NotEmpty() ) {
2806         OptoReg::Name kill = rm.find_first_elem();
2807         rm.Remove(kill);
2808         anti_do_def( b, n, kill, is_def );
2809       }
2810     } else {
2811       // Get DEF'd registers the normal way
2812       anti_do_def( b, n, _regalloc->get_reg_first(n), is_def );
2813       anti_do_def( b, n, _regalloc->get_reg_second(n), is_def );
2814     }
2815 
2816     // Kill projections on a branch should appear to occur on the
2817     // branch, not afterwards, so grab the masks from the projections
2818     // and process them.
2819     if (n->is_MachBranch() || n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_Jump) {
2820       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2821         Node* use = n->fast_out(i);
2822         if (use->is_Proj()) {
2823           RegMask rm = use->out_RegMask();// Make local copy
2824           while( rm.is_NotEmpty() ) {
2825             OptoReg::Name kill = rm.find_first_elem();
2826             rm.Remove(kill);
2827             anti_do_def( b, n, kill, false );
2828           }
2829         }
2830       }
2831     }
2832 
2833     // Check each register used by this instruction for a following DEF/KILL
2834     // that must occur afterward and requires an anti-dependence edge.
2835     for( uint j=0; j<n->req(); j++ ) {
2836       Node *def = n->in(j);
2837       if( def ) {
2838         assert( !def->is_MachProj() || def->ideal_reg() != MachProjNode::fat_proj, "" );
2839         anti_do_use( b, n, _regalloc->get_reg_first(def) );
2840         anti_do_use( b, n, _regalloc->get_reg_second(def) );
2841       }
2842     }
2843     // Do not allow defs of new derived values to float above GC
2844     // points unless the base is definitely available at the GC point.
2845 
2846     Node *m = b->get_node(i);
2847 
2848     // Add precedence edge from following safepoint to use of derived pointer
2849     if( last_safept_node != end_node &&
2850         m != last_safept_node) {
2851       for (uint k = 1; k < m->req(); k++) {
2852         const Type *t = m->in(k)->bottom_type();
2853         if( t->isa_oop_ptr() &&
2854             t->is_ptr()->offset() != 0 ) {
2855           last_safept_node->add_prec( m );
2856           break;
2857         }
2858       }
2859     }
2860 
2861     if( n->jvms() ) {           // Precedence edge from derived to safept
2862       // Check if last_safept_node was moved by pinch-point insertion in anti_do_use()
2863       if( b->get_node(last_safept) != last_safept_node ) {
2864         last_safept = b->find_node(last_safept_node);
2865       }
2866       for( uint j=last_safept; j > i; j-- ) {
2867         Node *mach = b->get_node(j);
2868         if( mach->is_Mach() && mach->as_Mach()->ideal_Opcode() == Op_AddP )
2869           mach->add_prec( n );
2870       }
2871       last_safept = i;
2872       last_safept_node = m;
2873     }
2874   }
2875 
2876   if (fat_proj_seen) {
2877     // Garbage collect pinch nodes that were not consumed.
2878     // They are usually created by a fat kill MachProj for a call.
2879     garbage_collect_pinch_nodes();
2880   }
2881 }
2882 
2883 // Garbage collect pinch nodes for reuse by other blocks.
2884 //
2885 // The block scheduler's insertion of anti-dependence
2886 // edges creates many pinch nodes when the block contains
2887 // 2 or more Calls.  A pinch node is used to prevent a
2888 // combinatorial explosion of edges.  If a set of kills for a
2889 // register is anti-dependent on a set of uses (or defs), rather
2890 // than adding an edge in the graph between each pair of kill
2891 // and use (or def), a pinch is inserted between them:
2892 //
2893 //            use1   use2  use3
2894 //                \   |   /
2895 //                 \  |  /
2896 //                  pinch
2897 //                 /  |  \
2898 //                /   |   \
2899 //            kill1 kill2 kill3
2900 //
2901 // One pinch node is created per register killed when
2902 // the second call is encountered during a backwards pass
2903 // over the block.  Most of these pinch nodes are never
2904 // wired into the graph because the register is never
2905 // used or def'ed in the block.
2906 //
2907 void Scheduling::garbage_collect_pinch_nodes() {
2908 #ifndef PRODUCT
2909     if (_cfg->C->trace_opto_output()) tty->print("Reclaimed pinch nodes:");
2910 #endif
2911     int trace_cnt = 0;
2912     for (uint k = 0; k < _reg_node.Size(); k++) {
2913       Node* pinch = _reg_node[k];
2914       if ((pinch != NULL) && pinch->Opcode() == Op_Node &&
2915           // no predecence input edges
2916           (pinch->req() == pinch->len() || pinch->in(pinch->req()) == NULL) ) {
2917         cleanup_pinch(pinch);
2918         _pinch_free_list.push(pinch);
2919         _reg_node.map(k, NULL);
2920 #ifndef PRODUCT
2921         if (_cfg->C->trace_opto_output()) {
2922           trace_cnt++;
2923           if (trace_cnt > 40) {
2924             tty->print("\n");
2925             trace_cnt = 0;
2926           }
2927           tty->print(" %d", pinch->_idx);
2928         }
2929 #endif
2930       }
2931     }
2932 #ifndef PRODUCT
2933     if (_cfg->C->trace_opto_output()) tty->print("\n");
2934 #endif
2935 }
2936 
2937 // Clean up a pinch node for reuse.
2938 void Scheduling::cleanup_pinch( Node *pinch ) {
2939   assert (pinch && pinch->Opcode() == Op_Node && pinch->req() == 1, "just checking");
2940 
2941   for (DUIterator_Last imin, i = pinch->last_outs(imin); i >= imin; ) {
2942     Node* use = pinch->last_out(i);
2943     uint uses_found = 0;
2944     for (uint j = use->req(); j < use->len(); j++) {
2945       if (use->in(j) == pinch) {
2946         use->rm_prec(j);
2947         uses_found++;
2948       }
2949     }
2950     assert(uses_found > 0, "must be a precedence edge");
2951     i -= uses_found;    // we deleted 1 or more copies of this edge
2952   }
2953   // May have a later_def entry
2954   pinch->set_req(0, NULL);
2955 }
2956 
2957 #ifndef PRODUCT
2958 
2959 void Scheduling::dump_available() const {
2960   tty->print("#Availist  ");
2961   for (uint i = 0; i < _available.size(); i++)
2962     tty->print(" N%d/l%d", _available[i]->_idx,_current_latency[_available[i]->_idx]);
2963   tty->cr();
2964 }
2965 
2966 // Print Scheduling Statistics
2967 void Scheduling::print_statistics() {
2968   // Print the size added by nops for bundling
2969   tty->print("Nops added %d bytes to total of %d bytes",
2970     _total_nop_size, _total_method_size);
2971   if (_total_method_size > 0)
2972     tty->print(", for %.2f%%",
2973       ((double)_total_nop_size) / ((double) _total_method_size) * 100.0);
2974   tty->print("\n");
2975 
2976   // Print the number of branch shadows filled
2977   if (Pipeline::_branch_has_delay_slot) {
2978     tty->print("Of %d branches, %d had unconditional delay slots filled",
2979       _total_branches, _total_unconditional_delays);
2980     if (_total_branches > 0)
2981       tty->print(", for %.2f%%",
2982         ((double)_total_unconditional_delays) / ((double)_total_branches) * 100.0);
2983     tty->print("\n");
2984   }
2985 
2986   uint total_instructions = 0, total_bundles = 0;
2987 
2988   for (uint i = 1; i <= Pipeline::_max_instrs_per_cycle; i++) {
2989     uint bundle_count   = _total_instructions_per_bundle[i];
2990     total_instructions += bundle_count * i;
2991     total_bundles      += bundle_count;
2992   }
2993 
2994   if (total_bundles > 0)
2995     tty->print("Average ILP (excluding nops) is %.2f\n",
2996       ((double)total_instructions) / ((double)total_bundles));
2997 }
2998 #endif